internet theft

On 9/28/2009 this company charged my debit card $44.99 I have never done business with this company, I have never heard of them, I have never filled out any forms or requested anything from them. I called this company on 9/30/2009 to see why I was charged. they said I had signed up for their service and I did not sign up or contact them in any way. When I asked for a refund, they said they could not give a refund untill I faxed them and said I did not want their service. I live on SSI disability as my only income.