MTN Service is Horrific!

They billed me for "Self Service Purchase" for R13 909, 56 on my invoice of July 2022. I have NOT purchased anything extra on my MTN Contract apart from normal cellphone use. My number is ***. Have complained, sent several e-mails and reported a case of ***** to SAPS Sinoville no CAS 93/10/2022. I paid the whole outstanding amount to lift the suspension and enable me to use my phone.