billing an cancelations

I was called for a contract deal for a tablet deal took the deal received the product called the same day to return the item in the cooling of period it took them a month to collect the tablet once they have collected the item immediately my bank account was billed R741.55 for cancelling the contract in the cooling of period when I was advised no billing or cancellation will Accor ******* and dishonest i am otherly disgusted with the ship service and the nerve to call me with a attitudes I ow them money