It’s taken Lara Davidson two years to be free from calls for mystery woman “Diana.”

The Toronto resident never met Diana, nor did she appreciate the 2 a.m. phone calls to go party. Banks, charities, financial institutions and an array of friends rang up this number asking to speak with her. Davidson made it clear to callers that she had no knowledge of this woman, so far as to include that information in her voicemail greeting.

Two months in, with the late-night texts getting to her, Davidson decided to explain this situation to one of the callers. Davidson said the number of erroneous calls declined after the friend sympathetically promised to get the word out that the number no longer belonged to the other woman.

“At this point I became a little concerned for this other person. It seemed that she simply fell off the face of the earth. I mean, in this age of Facebook and Twitter, and instant communication, I found it a little alarming that she could vanish for so long, from her circle of friends,” Davidson told in a telephone interview on Friday.

It’s an issue that seems unavoidable as phone companies ‘flip’ numbers around to new clients, re-issuing previously used numbers. Even the standard six-month period before a number can be recycled to someone new often isn’t enough to flee these leftover phone calls.

Consumers, however, can expect this trend to become increasingly common as demand grows for new numbers.

Canada already has 31 area codes in operation, with more in the pipe.  Toronto is among the target areas, with a third area code, 437, coming on March 25, 2013. In the next few years, expect to see five or six more.

The reason for recycling numbers is quite simple – we don’t want to run out. But that might happen sooner than you’d think.

According to the Canadian Numbering Administration, phone numbers in this country are expected to run out in the next 30 years. 

While that may seem long to some, the added strain of smart phone apps and appliances that are suddenly requiring telephone numbers is reducing that 30-year time frame drastically, says CNA director Glenn Pilley. Pilley offered the new Dell VoiP Windows Phone app as an example. The app helps cut down on mobile phone bills by offering free calls over WiFi, and a free phone number is included. 

The CNA belongs to the larger North American Number Plan that oversees millions of ten-digit area code numbers assigned to Canadians.

According to Pilley, approximately 60 million phone numbers, wireless and landline, are in use in Canada right now. The wireless industry averages about 1.5 million new subscribers per year for the last four years. More new numbers are available, but NANPA puts limits on releasing these numbers to combat phone companies from snatching up huge blocks of numbers.

A company has to dip down to less than six months of phone number inventory before they are assigned new blocks. So in an effort to maximize the available numbers, companies begin to re-issue old numbers.

Thankfully for consumers, this process isn’t happening overnight. Companies are still required to hold onto old numbers for a minimum time period.

Pilley said landline companies normally take six months to recycle a number. Some high-volume numbers, such as call-in numbers, sit for a year, he said.

According to individual telecom companies, this holding period seems to vary, however. Telus’ standard is 90 days before they re-issue a number. Rogers and Fido said they abide by the CRTC’s standards which are one to three months for wireless and landline numbers. For business it can range anywhere between three and 12 months.

Compared to the six-month period Pilley indicated, Bell said it holds mobile numbers for 90 days before they re-issue them. They also give the previous owner those same three-months to take the number back at any time.

If an area code is expected to run out of new numbers, these time periods are cut down by a third, said Pilley.

Swift switchovers may have been the reason Toronto resident Nic Morgan woke up to a phone call one day telling him he wasn’t pregnant.

For a year, Morgan fielded calls for a woman named “Nico” on his university dorm landline. Ex-boyfriends, video rental stores, screeching girls and a caller who refused to believe she wasn’t around to answer the phone rang in.

One particular Saturday, being half-asleep, Morgan picked up the phone misinterpreting “Nico” for “Nic.” What followed was a doctors’ office informing him that all the tests came back negative and that he wasn’t pregnant.  Dazed and confused, Morgan responded saying “yes I know,” and hung up.

The doctor’s office did call back and Morgan continued to receive calls until he gave up the line at the end of his first year. “I do remember complaining to a couple friends that I got more calls for Nico than I did for myself,” he said.

Moran said some of the responsibility has to go on “Nico” as she didn’t seem to update her phone number with those she shared it with.

“I would be very upset if I found out my doctor called and gave away private info,” he added.

Even high profile cases of mixed lines have been reported.Rapper Lil’ Wayne announced on his Twitter in 2009 that his lines got crossed with singer-actress Miley Cyrus. After receiving the young star’s old line he reported getting constant calls from friends of Cyrus.

A more frightening example was reported by the Orlando Sentinel in June of this year explaining the case of 49-year-old Junior Alexander Guy. The man who bought a cellphone for the first time started receiving death threats. It turned out to be a number formerly used by George Zimmerman, the man who shot and killed Trayvon Martin in February 2012. It was reported that the number has since been retired.

It all comes down to regulatory practice and the responsibility of service providers, said John Manning senior director at NANPA.

Telus says they would replace phone numbers free of charge if customers complained about receiving calls for the previous person.

“It’s a difficult situation, whoever gets these numbers, there is an opportunity for people to make phone calls thinking they’ve reached the previous owner,” said Manning.

And the industry shows no signs of slowing down.

“I think the responsibility to protect privacy is on the people making the call. If it’s a privacy issue it’s entirely the caller,” said Morgan.