MTN PAID UP LETTER

I requested immediate issue of my paid up letter from MTN, my accounts were not in arrears or handed over nonetheless MTN is telling me about 21 days, right now m losing out on a property because i need that letter to finalise my finance application, 21 days wait period for paid up letter is crazy, all other businesses issue the letter immediately without this utter ******* of 21 days, M DONE WITH MTN .