Billing / Accounts Irregularities

Hi, name is Philip and my policy number is ***, i placed a debit order on it for the 26th of every month, i phoned last month to make sure the debit order went through to which i was told it did, but at 8:35 last night i got a notification of an attempted withdrawal from hollard, i went into my transaction and you did a withdrawal and reversal on my account for 864.07 which shouldnt be, my initial payment was 864.07, subsequent ones should be less 200, anyways i need explanation as to why you guys are going into my accounts when you shouldnt, because its not the 26th. this is unacceptable and a breach of my privacy, i get charged with every transaction and youve cost me money... i need answers...