Zest Money — Never received refund

I have placed an order on Amazon through Zest Money. LOAN was approved but order was cancelled. CONTACTed Amazon and redirected me to Zest Money.
CONTACTed Zest and they asked me to provide cancellation email's screenshot which I provided right away and they said that refund has been processed and will be CREDited back within 7-10 business days. I wait for 10 business days and CONTACTed back, they asked me to wait again. Since then I have CONTACTed several times but everytime they ask me to wait. Its been 22 days but didn't get refund. Their phone number never works. Asked to escalate the case to manager and got the same response to wait more.
I am blank at the moment and don't know what to do to get refund of 25K.Repayment date is approaching and if I miss to pay then it will affect my cibil score.
I will never use Zest money and will not recommend anyone to use it as it has ### CUSTOMER service I have ever come across.
Please let me know where I can complaint to get this resolved.