PNB — Refund not credited yet

I have ordered some items from jio mart on[protected] and i paid it online itself, and i cancelled it on the same day and they have initiated the refund on 16th December but the amount is not yet credited yet, when i ask about it on jiomart they said they have done everything on their part for the refund and also provided the refund reference number now its banks issue to do the rest...but when i call the pnb they are also not giving a solution or nothing they are saying the reference is not useful for them i am providing the reference number below 75503720349044384668252