Shady Billing Practices

I was contacted by this company for a promotion. Two days prior to the end of the promotion period I called and cancelled all services with them. Today, 2 1/2 weeks later a charge appeared on my account. I called to clear up the matter and was unsuccessful. A supervisor called to clear up the matter and stated that I would in fact be charged and no credit would be issued. He insisted that my stating I did not want any of their services did not matter because I agreed to have someone resend me an email with information that I had not previously received.