CALGARY -- As many as 15 per cent of working age Albertans don't file annual federal income tax returns says a financial counselling non-profit. It's costing low income earners thousands of dollars in potentially life-changing benefits.

"So think of a single mom maybe struggling to get by earning less than $30,000 a year, if she files her taxes, she can get up to $10-thousand dollars in benefits from the Alberta and the Canada child benefit," said Jeff Loomis, executive director of Momentum.

E. Grey said his life was changed by simply catching up years of missing tax returns.

"It's a whole load off my shoulders," Grey said. "It feels wonderful now, but six months ago I was in a pretty dark place."

He was homeless and lived on the street for about 10 years, suffering from a deep depression that he says caused him to retreat from just about everything in life.

He asked not to have his full name used, embarrassed and concerned it could cost him future job opportunities.

"I was able to get some GST money back because of filing, and that was enough to get me to be able to pay a damage deposit and get me into a real place again."

Last year Momentum helped about 6,000 Calgarians with financial and business advice, free of charge. Together it resulted in more than $40million in benefits and refunds payed out, says Loomis.

"It's a really complex system for a lot of people, to be able to navigate, especially say if you're new to Canada and have language barriers, or they just don't know where they can go to get help," Loomis said.

"If people don't file their taxes, they're missing out on huge benefits that can make a huge difference in their life."

As for Grey, he now has a permanent home and a vehicle to get around in. He hopes others who might feel financially desperate follow his lead, get help to file past taxes.

"Even if you owe money, they're going to see on the system that you're not making money, they'll understand," he said.

"Whatever it takes, make that phone call, start the conversation, it's going to change your life."

You can find help by calling 211 which will put you in touch with free assistance.