I want my paid up letter

I have been calling this trash company for 3 months now for a paid up letter. Every time when I call them it’s excuses excuses. I even regret why I paid them in the first place. I called them again today, did the lady not hang up on me while I was still talking. Please I need my paid up letter, for that matter I was owing mtn and not you. Your customer service is so filthy