VAUGHAN, Ont. -- A 74-year-old Canadian businessman sentenced in Cuba to 15 years in prison on corruption-related charges is determined to clear his name, his son said Monday during an emotional plea for his father's release.

Cy Tokmakjian, who owns the Ontario-based automotive company Tokmakjian Group, and two Canadians working for his company have been sentenced to long prison terms, the firm said, calling them victims of a campaign by Havana's Communist government to rid the country of what it calls a culture of bribes.

Raffi Tokmakjian said his father is a proud man with the "utmost integrity" who has been doing business in Cuba for over 20 years. While he hasn't seen his father since he was detained three years ago, they have spoken over the phone.

"Every time he calls he reminds us, he says, 'I've done nothing, you know that. Everybody knows that. You cannot stop fighting for what's right,"' he said during a news conference with his family in Vaughan, north of Toronto.

"'They've already taken three years of my life, but I will not admit to anything I have not done."'

His father, who is currently in a Cuban military hospital due to poor health, has done business for more than 40 years both in Canada and abroad without any problem because he ran his affairs "appropriately in accordance with every single law in the jurisdictions," he said. The company has offices in Panama, Nicaragua, Barbados, the Dominican Republic and Korea.

Two other Canadians -- managers Claudio Vetere and Marco Puche -- received 12- and eight-year sentences respectively, according to company officials.

One of the "absurd" charges was economic crimes against the state for the late delivery of equipment, said Lee Hacker, the company's vice-president of finance.

In fact, the company has gone out of its way to help Cuba, he said. It shipped millions of dollars worth of cars to the Caribbean country in time for tourist season, even though contracts weren't signed, he said. They didn't collect money owed by their customers for four or five years.

It appears the Cuban government simply wanted to seize the company's assets, which had taken Tokmakjian decades to build, Hacker said.

Cuba's judicial system is known for speedy proceedings behind closed doors with little or no media access. Cuban officials have said little about the Tokmakjian case beyond announcing last year that the Tokmakjian Group's operating licence had been rescinded due to unspecified actions.

The investigation was kept secret for two-and-a-half years, Hacker said. The trial was a "complete sham" with key witnesses, including Cubans living outside the country, not allowed to testify.

"They portray this corruption campaign as something good that they're doing," he said. "But in reality, there's something very sinister that is happening in Cuba. This has happened not only to Tokmakjian but to other foreign businessmen in Cuba."

The company's Cuban offices were raided in 2011 as the country launched an anti-graft drive that has swept up foreign business executives from at least five nations as well as government officials and dozens of Cuban employees at key state-run companies.

Hacker said like other companies in Cuba, it paid "incentives" to workers, since they can't work directly for the company and must collect their salary from the state. Businesses would give their wages to the local payroll office, but the workers would see very little of it -- it wasn't enough to live on, he said.

The Cuban government made those incentives legal five years ago, Hacker added. Incentives were also paid to employees of Tokmakjian's joint ventures with the Cuban government, but there was no link between those payments and any advantage to the company.

Foreign business people have long considered payoffs ranging from a free meal to cash deposits in overseas accounts to be an unavoidable cost of doing business in Cuba. President Raul Castro has said that rooting out rampant corruption is one of the country's most important challenges.

More than 150 foreign business people and dozens of small South American and European companies have been kicked out of the country under the anti-graft drive. Several dozen defendants have ended up in jail, including a few foreigners and high government officials accused of influence-peddling and taking bribes.

Such cases, and questions about their fairness, have chilled many current and potential investors in Cuba, which is trying to attract foreign capital to jumpstart the stagnant economy.

MP Peter Kent, whose Thornhill riding includes the company's headquarters, said that Tokmakjian should be sent back home, calling the conviction a "travesty of justice."

He could be expelled from Cuba or transferred to a Canadian facility instead of serving out his sentence there, Kent said.

Tokmakjian's family said it has received a lot of help from officials with the Department of Foreign Affairs.

His son, Raffi, said he was concerned about his father's health. He said the man fell from his bunk bed and got injured.

"It's devastating," Raffi said as he fought back tears.

"Justice is not prevailing. If it was, he should be home and he's not. He needs to come home."