The Ontario Energy Group and its director have been charged with 142 counts of violating the Consumer Protection Act following a provincial investigation into hundreds of customer complaints against the door-to-door sales firm.

The Ministry of Government and Consumer Services began getting complaints in 2009 about the business, which sells air-conditioning units, water heaters and furnaces, ministry spokeswoman Anne-Marie Flanagan told CBC News.

The provincial investigation resulted in the charges laid Friday, which include using false, misleading or deceptive practices, failure to deliver a valid contract and failure to issue a refund.

When asked why it took so long for the province to act, Flanagan said the ministry needed to "take time" to do the investigation and get it right. She did not say when investigators began looking into the reports about the firm.

"This is definitely a situation that we take very seriously and that's why we are acting," Flanagan told CBC.

Those charges are connected to 20 complaints from across Ontario that have been levelled against both the firm and its director, Eugene Farber. Farber and the company each face 71 charges.

'It was a trick, they told a lie'

A complaint from Desmond Greaves about the firm led to some of the charges. The Etobicoke man alleges Ontario Energy Group promised him a fixed gas rate in April 2014, but instead took out his heating equipment and began sending him invoices for what they installed.

"The guy told us the government had a program and they were supposed to adjust the equipment for the heat so [we] would only be paying $119 a month, maximum."

The new equipment had no effect on the price of his gas, he said, and Greaves realized his heater had been taken. When he asked that they return the two-year-old heater he bought for $6,200, they told him it was gone.

Greaves and his partner, Mavis Williams, are seniors. The Etobicoke man has had two strokes. He said the company did not approach his neighbours and believes that he was targeted because he seemed vulnerable.

"They said they were going to give us a cut rate on the gas bill," he said. "But it was a trick, they told a lie."

Compliance order

Alongside the charges, the province has also issued an immediate compliance order. But Flanagan could not say exactly how the ministry would enforce that.

Each charge carries a maximum fine of $250,000 for companies and $50,000 for individuals. Farber could also face up to two years in prison if convicted on any of the charges, none of which have been proven in court.

Neither Farber nor anyone else from the firm has yet returned calls from CBC News for comment. But a lawyer representing Ontario Energy Group, Pradeep Chand, said that his "client fully intends to defend the allegations ... and categorically denies any regulatory or civil liability."

A hearing will take place in the Ontario Court of Justice in Newmarket on May 27.