Parimatch - Withdrawal amount didn t received

I have placed a withdrawal request of Rs.**,*** on **-**-****. It's **-**-**** still didn't received funds in my account. When I contacted parimatch regarding this issue they are giving me a reference number and asking me to check with my bank. I asked my bank and they are saying that they didn't receive any update regarding that reference number and asking to contact sender's (Parimatch) bank. Now parimatch is asking official letter from my bank regarding this issue. How come any bank gives official letter when the transaction didn't received to their end? I shared the email screenshot copy from bank's customer care but Parimatch is asking official letter. When I asked for transaction details Parimatch is giving me only reference number instead of sender and receiver details, transaction date etc., like a receipt. Please kindly resolve this issue.