Double Payment taken

Matrix took a double payment off my Account in November, and the tried again to take a double payment in December, on phoning the call center they say I am up to date with my account, however Matrix still debiting my account twice every month, Please note this is breach of contract and you have 7 days to rectify, should you not rectify I will be canceling my contract immediately without penalty .. legal cost to cancel this will also be for your account and you are in breach of the contract signed, refer to payment T & C of the agreement