Tom Sada, owner of Komoka Foodtown, signed up with a third-party electricity retailer, thinking it would lead to savings.
Instead, his bills have jumped by hundreds of dollars a month.
"I was supposed to save, not pay eight, nine hundred dollars more," Sada said in an interview. "To me, it's a scam."
But contracts with Just Energy Ontario LP don't promise savings, only price stability.
Sada said that's not the sales pitch he got. His store is not consuming more energy, but his bills keep rising, he said.
This month topped out at $5,440.01, versus $3513.68 last year when he was still with Hydro One, the provincially owned utility.
"If you pay just for hydro five, six thousand dollars, how much produce I have to sell?"
Just Energy declined a recorded interview with CBC News, but said it pre-purchases its electricity, which is one of the reasons its rates differ from Hydro One's.
The company is one of 16 third parties licensed to sell electricity in Ontario. Between them, they have less than 10 per cent of the market share. Most offer fixed rates over multi-year terms, instead of prices that can increase every six months with a publicly owned utility.
But that doesn't always translate into financial savings, which has led to scores of complaints about many of those companies to the province's energy regulator, the Ontario Energy Board.
Energy contracts are the most common issue for calls to the OEB's consumer-relations centre.
Those complaints are tracked on its website, which shows that Just Energy is far from the worst of the lot. Last year, there were, on average, a half-dozen complaints against the company for every 1,000 of its customers.
Other companies had tens and even hundreds of complaints per 1,000 customers.
Just Energy has paid more than $130,000 in penalties over the years amid allegations that, among other things, it misled its customers.
Read the fine print, OEB advises
The OEB's communications manager, Alan Findlay, said it's not always the company that gets it wrong.
"Read the conditions and terms of the contract," he advised. "All that's very important because it is a contract that the customer is signing."
Sada acknowledged he didn't read the fine print as closely as he should have. But he said he still wants out of the agreement he signed.
Just Energy initially said it would break the contract for $80,000, then reduced it to $40,000. After CBC News starting making calls, that price has dropped to just under $7,834.
Sada initially said he wouldn't accept, and launched a complaint.
But Thursday afternoon, he said he had struck a deal with Just Energy to get a lower rate and will stick with his contract. He wouldn't say how much he'll be paying.