Nimble Group
Paid up the account but Not getting the lette

I had a Capitec account in arrears which I settled on the 16th f January with Nimble collection Services, and I was told that they will pay their client "Capitec" by the 28th of January, then I will get my letter stating that the account is settled and update the ITC. Until today I have spoken to three different people in the call centre and everyone keeps telling me they will send the letter when I get off the phone but nothing has come of it!! I have paid them and now they won't even give me proof of that payment.