Settlement Complaint

I dealt with Mikalya Elliot (customer care agent) since 30 Aug for a settlement amount of which I received 4 Sep and immediately paid with proof sent to her. I was told of a 7-21 days waiting period for a settlement letter to be generated. 23 days later, Mikalya Elliot tells me of an outstanding balance remaining on the account as there was no settlement agreement! No response from emails since 27 Sep. Calling is a waste of airtime as you're on hold for ages! How can I be given a settlement amount by an agent who later tells me no agreement was in place???? Am I seriously expected to still make a payment after the account was settled??? WORST company to deal with!