debit order

on the 16 January 2016 i got debit order on Roving Jetrj ***, these guys the called on my mobile number *** advertising their reward a week before and i told them um not interested in their what so ever product, then the next thing they debited 99R on my account how did there get my details id number and my account details , who authorized them to deduct my money and i never signed anything with them. please assist me on suing them