Don't want to Refund my money

They deducted a fee they said they forgot to charge me for whole previous year which was not communicated to me and I did accept n now this current month they deducted again that very same fee and I inquired what was it for and they said it was a mistake it will be refunded in my account within 14 working days and now when iam calling them its story after story the problem with car track they just debit as they feel like and when i asked to pay through EFT they said i must pay 3 months in advance but anyway I am going to cancel the debit order and If I cant pay through EFT its their own fault And mind you this is not the first incident last time they never refunded me, this time I won't let it slide