Pepper are slow to do anything.
But process is:
1. Ask for redemption figures from them.
2. Pay them the quoted figure or , if they are slow to provide, pay what you believe is due.
3. Ask for the Mortgage Deed to have a Release/Receipt endorsed on the Deed so that evidence of discharge can be registered in the Registry of Deeds (if unregistered title) or an e-Discharge filed in the PRAI if title is registered.
For completeness, OP should ( I personally think) do all this through the solicitor.
mf