Getting a paidup letter is a mission impossible

I have recently paid off my personal loan with FNB, the loan had been handed over to Easton Barron Attorneys for collections, this is the Company I have been making payments to up until my last instalment on the 27th December. I have been calling them almost daily to request a paidup letter so that I can submit it to the Transunion for an update on my credit profile, every time I speak to the lady by the name of Thobeka, who is supposedly in charge of my account, she keeps on telling me the letter is being emailed or was emailed to me but on my side there is no letter received. Due to now feeling frustrated I then decided to call FNB, I ended up speaking to about 5 agents, being taken from pillar to post, still I am not getting any help. I am at the point where I do not know what to do. I feel so let down.