UNAUTHORIZED BILLING ON MY BANK ACCOUNT

I recieved a call from a telesales agent and was offered a contract, during that conversation, the agent offered me added services to which i declined. i was declined the contract due to me being on ITC yet come monthend, i was debited for services i refused to take. one of these services was from PHONE BOX. I would like my bank account to be refunded and any future debits regarding this service to be stopped immediately.