INVALID REFERENCE, A583***** I CAN'T SETTLE MY ACCOUNT !!!!

I am so FRUSTRATED with MTN. I have been trying to settle my account and no one seems to know what their doing. I have been transferred from pillar to post and the reference I was provided with to settle this account is INVALID. I have tried all three banks and no bank is accepting this reference. I am so ANGRY with MTN. I honestly regret taking a contract there and I will never even recommend it to my closest friends nor relatives. Absolutely useless!