CellC - Paid up letter

I was handed over by cellc to ssda because I had an account with cellc ,then I settled the account in 2021 December, been trying to get a paid up letter since then to date.the company that I was dealing with told me they are waiting for cellc to send it to them ,but it's been a while ,I tried calling cellc myself but still getting empty promises, I really don't know what to do. It's almost a year now ,still no help.