MBD WORST SURVIVE. PAID UP LETTER NOT RECEIVED

I paid up my account a couple years back. They never sent a paid up letter. I found out that MBD is on the red flag list saying that I haven't paid. So I speak to someone named Joseph and he says my account was paid up. He said he will request a paid up letter. I have not gotten feedback. I told them it was urgent. I made 15 phone calls to them (I'm not even exaggerating) I spoke to many agents who either put me on hold then the phone dies, or tells me that my account is paid up but was handed to someone else (makes no sense) or they want the date of the paid up account . I NEED MY PAID UP LETTER. my life is at a stand still because of these people.