Dri Shopper shopper systems Starving Graduate student taken advantage of! Emailed to cancel but was still charged $49.99 anyways! Internet

I am starving graduate student who is looking for extra money to pay the rent. So naturally, when I was called by this company and given the impression that I could make $50 for every secret shopper visit I could complete I took it as a great opportunity. I signed up for the 7 day trial period under the impression that I would not be charged anything unless I decided to continue with their membership at $49.99 a month. 
The first day I signed up I went to their site and applied to probably 20 jobs. Even though none of them payed $50. Each job only paid about $8 and required you buy something first. I decided it wasn't worth it so the day before my 7th FREE day, I sent an email to customer support stating I would like to cancel my membership. A few days later I will billed $49.99!
I went to my bank account and found 2 more random charges of $3.95 and $2.95! I called customer service and explained that I did in fact cancel and would like to have my money back. They refused saying they didn't receive my email and even when I asked if I could forward it for proof they said there was nothing they could do. RIP-OFF!!!! I want my money back!