Installment Recalculation after Account Settlements

I have been waiting two months for a recalculation of my installments after settling some accounts. Even after sending proof of settlement and receiving paid off letters, they are still paying funds into those accounts! I am still informed to pay my full installments, even though it should have come down. Nobody responds to my emails, not even the complaints department. I have not even received as much as an acknowledgement of my complaints. Absolutely the most useless and *********** company I have ever had the misfortune of dealing with.