Delhi Development Authority [DDA] — stating me that I won't get my, refund 2 00 000 whereas I submit application for surrender of flat and refund of money

I am one of applicant who applied for dda housing scheme 2019 my name is Diksha Monga applied through Kotak bank application no 1101078.
the result of draw were declared on 23 jul and i was given narela LIG flat G7 1217. I went to DDA office on 24 jul and surrendered flat as i was not interested to buy that and requested for refund. i got refund reciept from them as well. but on 25 JUL i got call from Surinder Kumar addressed him as Asst. manager contact no [protected] stating me to come dda office on friday 26 JUL and meet him as they need some more documents otherwise i will not get my refund back. i said why you calling me from personal no. and if that was so how come you have given me receipt. and then he just said word " theek h phirr bhul jao apne paise nhi milega refund"