paid up letter

My homechoice account was handed over to them for collection. Then i called them to get the exact amount i owed. They gave me the amount and told them will settle the account on 16/04 and asked for a letter of settlement. The lady i spoke to said will get the letter as soon as the payment reflects. Called them on 18/04 was told the account is closed and will get the letter in 48 hours. Called them again on 20/04 & was told i will recieve the letter today i call spoke to a rude lady noluvuyo who was so rude and tells me i am not their only client and i must wait for 7 to 14 days and then hang up the phone on my ear. I need that letter asap need to submit it somewhere today.