Rs It Data Entry Services — they are torturing me to pay the amount

I got a call from rs it services guntur, they said we will give 15000 if qc report is 90 or above for filling 1000 forms in 7 days in which they will deduct 4000as registration fees. I have agreed and done the work, submitted for qc report in time. They now manipulated the data and asking for money. I completely cheated. Please take necessary action and cancel my agreement. They send me a notice also please help me to get rid of this pblm. They are mentally torturing me