Zestmoney — Refund amount not received

Dear Team, i have taken a loan with No cost EMI of Rs 250000 from Aug'22 from Zest money. Zest money give me cash back after paying my EMI with Interest Amount. interest amount is my cash back amount. but it has been passed more then 1 month (28 Feb 2023) and i have paid my next EMI (31 Mar 2023) also but they are not returning my cash back amount. i have called to customer care multiple time and they are not giving me proper time.
my total EMI is 22400 out of with 1519 is my Cash back Interest amount.