Very irate customer! Service beyond pathetic!

Another mess up by MTN!!! This time is my billing they messed up. I have been calling the call centre but found no joy! The consultant called Gift put me on hold for 20 minutes and drop the call!!! How pathetic can you be?! I have signed for a contract that I supposed to pay R550 in total but guess what? My bill was R1001 which included my old handset installment. When I processed my upgrade in store, the consultant advised me that my old handset installment will fall away but clearly that didnt happened. Your call centre is useless and it seems that your social media team is on holiday. I want my bill to be rectified now!!!! Thank you Mike from the Hello Peter team that fixed my data problem. It is much appreciated. Please resolve my issue.