No accountability on "missing funds"!

The same monthly amount was paid to EZ Mediation. Their statements showed that one of the accounts had a steadily declining balance and was eventually marked as paid up. After that, the funds were allocated to other accounts. Two years later, the creditor advised that the account still reflected the original outstanding balance and that no payments had ever been received from EZ Mediation. Despite their own records showing allocations to this account and a decreasing balance, EZ Mediation denies responsibility for the missing funds. It is clear that the money allocated to the account was not paid over to the creditor. EZ Mediation has now informed me that I remain liable for the full outstanding amount.