MTN ,Not doing stuff fairly

MTN

I have a MTN contract ,and was handed over ,that was fairly ,But my issue is i have being called and bugged the whole time ,i did make arrangements and it was paid up in full ,now that i request for a paid up letter i being ignored ,send emails upon emails out ,with no luck ,and ask for paid up letter ,everyone ignores me but ,if they need something from you they fast to complaint and complaint but when you do your part they just flat ignore you ,which i think is not fair ,what a bull**** , i have all the mails ,as proof