Incompetence is an understatement

It's been almost 7 months of being sent from pillar to post by MTN and Mondo, after Mondo did an incorrect upgrade. This statement and invoice still reflect the amount that was supposed to be credited due to the mistake you guys made.

Nobody seems to be able to assist with this. The last email I received from Mondo was that the reversal was done and my number credited but it still has not reflected on my MTN account. First your call centre messed up my upgrade, then messed up the reversal/cancellation and just to put the cherry on top..... you even mess up the credit.

Can someone that actually knows what they are doing, please resolve this asap? Reference is RCO408771