Cancellation of Wifi Contract

I have cancelled my WIfi contract in July. Twice telephonically, I've emailed the cancellation form three times and I went into Greenstone's store to cancel it. But every month my account is debited. You claim on Hello Peter that you will contact me but no one did! Completely disgusted with your lack of response. But yet again you debit my account. My bank sent the debit back and blocked you from debiting my account but you changed the reference number and double debited my account! Its disgusting how you ***** from people!!!