Bank Balances Keep Changing

Hello,

I am new to FA. Started utilizing bank reconciliations with balance of 0.00 then inputted proper ending balance. Continued to next month and the starting balance is out $500.00. So I go to change to correct amount and it never saves. I then found a prior unrelated reconciliation of $500.00 that should not exist. Is there a way of deleting this reconciliation and forcing my starting numbers to be 0.00 ?