Pathetic customer service from MTN

Pathetic customer service from MTN. I have been trying since end of April 2020 to sort out a billing query to the value of over R23000 with MTN.I went to 3 different branches several times,phoned the 135 helpline to speak to a so-called “Service Champion”and sent numerous emails to customer service,just to be given another reference number.A few days later I would receive an sms stating that the case had been closed,but I would still have no answer to my query!In the process I have logged over 12 queries!I also requested itemised billing for February and March,just to be told that the system only allowed them to provide me with the last 3 months’ itemised bills,because MTN switched over to a new system!?I even went to MTN head office as advised by one of their “Service Champions”,just be told by a security guard that all staff were working from home during lockdown! I have been a loyal MTN customer for over 15 years.I find this lack of customer service a slap in the face!Come on MTN,I need this resolved!