Paid Up Letter Request

My Edcon Account was handed over to MBD Attorneys. I have finished paying the debt and I believed I have paid more and the credits need to be reversed back to me.Cant get hold of your call centre they never call back or email back. I haven't even received a pid up letter I would like the matter treated with urgency as it won't be fair that I escalate directly to the CEO. This treatment is not acceptable and violates all the consumer rights and this is unprofessional,******** and not acceptable. Urgently liaise with me for this to be resolved