Unauthorised deduction on my account

Beginning of march i received a call from the lady called Dorah saying she is calling from hotelexpress international that i have won something sort of a trip or whatever and she did got my personal details together with my account details because i was excited by then.From the 19/03 to 27/03/2015 they kept on calling and they couldn't get hold of me because i put their number on rejection list because i was smelling something that they might be ****s,guess what today they deducted almost whole of my salary and i don`t know what to do as you know very well that we have some bills and stop orders,yet somebody decided to get your money out of nothing without anything written and signed on a paper