FIRST, COMPANY HAS FIRST YEAR TAX DUE INSTEAD OF MINIMUM TAX DUE $800. SO HOW TO ADD 2021 TAX YEAR $800 (100- ES) PREPAYMENT ON THE CURRENT YEAR TAX DUE? 

SECOND, MY CLIENTS KEEP RECEIVING LETTERS FROM FTB REGARDING ESTIMATE PENALTY BUT MY CLIENTS DID MAKE THE $800 PREPAYMENT ON TIME. DO YOU KNOW WHAT IS THE REASON?

THANK YOU!