fraud Idea

maine apne nazdiki retailer se idea connection liya 4/3/2016 yeh last bill hai jab iska payment kiya tha to usne 500 /-security se yeh bill adjust kar diya tha cash se nahi wo bhi galat no. par aur kah r tha 500/- security k connection band hone k 45 days bad cheque ayigi 45 days bad jab cheque nahi ayi to usne kaha payment galat no. par ho gaya hai no. galat usne dala hai na slip its not my mistake , so plz help me for return my money back