Paid up letter

I have been requesting for a paid up letter from vodacom but till to date nothing... I was told that I owe R692, I have to pay it then send a pop so they can process my request... done that but still no response from them.

Called a couple of times and all the agents would say we have escalated your request, I should get my Paid up letter within 24 - 48 hours but nothing.

Please kindly assist.