Constant harassment even after arrangement has been made with creditors

Account was handed to them after had spoken to my creditors why there was no payment. A payment arrangement was met between me and my creditor and it was noted on there system, but two of mbd's consultants by the name of blessing and thando keep calling me and inflating the outstanding balance by twice the amount due even after I have made payment on the account. MBD are *******s they are like hungry blood sucking vultures.