MTN *****s R5000 airtime on my MTN Contract

So MTN, I have been struggling since LAST YEAR September with this account. R5000 worth of airtime was ****** from me. Because MTN has people I suppose that know how the system works. And I had R5000 worth of Airtime ****** because MTN, your anti-***** system does NOT work! You know what MTN did, South Africa, hope you all can see this, gave me a credit of R5000 worth of Data, instead of a credit, but then I still have to pay the R5000! And then, after I said I need you to CREDIT my account with the R5000 ****** from me! YOU take away the data as well? I cannot upgrade, because you did not credit my account with the R5000 ******, I pay my normal contract amount due, EVERY single month. BUT I will NOT pay the R5000 ****** from me on my MTN account. So credit my darn account like you are supposed to! Charles. ***