First national bank

I've had a loan with fnb and it's been paid up, but after i checked my credit profile I saw that I still owe fnb money, so what the hell is going on with you guys!!???, because I can't apply for credit because the loan has suddenly been listed as a adverse account in the exact same day that I've Sended them proof of my payment, I've contacted them numerous times and not to mention all the airtime I've wasted, because none of these call centre people could help me they are truly useless!!!! ... I will never take out a loan with fnb again, what are you guys getting out of this is to ruin someone's life so drastically for the next following years, you must remember you are all working for fnb, but once you walk out of there you all become individuals on your own, wich means what you do to us will eventually be done to you in return by the same ban****