Very BAD service!!

On 15 August they deducted an installment, I phoned and they said they will refund. On 16 August they deducted again and I phoned and they said they will refund. I said to cancell the debit order as they are taking money out of my account for two days now and the date for debit order is on the 25th. This is unacceptable as they cannot tell me why they randomly deducted twice in one week, if they have your bank account number they take money out of the account as they wish. I want to cancell the contract and they let me know I have to pay R5000+. This is ridiculous!! What about the bankcharges that I have to pay for their indescreprancies!!