Accelerit Double Debit Customers

I recently had an issue with Accelerit ISP where I was double debited and furthermore, the money taken from my account, was taken without my consent. Here is what is written on their package offer: "Best of all - our packages are prepaid this meaning you can skip monthly payments should you wish to and we will not penalize you!" My banking details were saved and then used to debit my account without my consent. Upon questioning what happened to my money, I too was told that the matter is being investigated. Accelerit has said that there is a number of customers who have been double debited and they are aware that this is an issue. My problem is that they are not returning the money. If you are aware that there is an issue, what is so difficult about returning money which belongs to the customer. Furthermore, I have sent in statements, as well as invoices showing that I had paid for each month of service, however it is still an issue to return my money.