Refuse to pay my money back

I, Johannes Jacobus Gerber phoned Mweb a couple of months ago to subscribe to their internet services.<br> The sales person told me that the contract is on a month to month basis. They then send me a form that is based on a year contract. I then told the sales person that I am no more interested in this contract. All of a sudden Mweb starts to subtract money from my account. I have never activated the account nor using their services. I phoned them a couple of times to complain about this and ask them to pay my money back, they said that they will investigate this and come back to me. So far nobody came back to me and they took another payment from my bank account this month. Please help!!!! They owe me more than R 644.00 up to now.