MTN - change of surname and adres

I have been struggling since March 2024 to have my surname and adres changed on my MTN account/statements. I have phoned 135 multiple times and have gone into different MTN stores to help me with this issue. Each time they log a ticket to have it changed. They assure me by the next month’s statement everything wil be sorted out. Each month my statement comes and my surname and adres is still not changed. I don't know what to do anymore and I need to use this MTN statement as my proof of adres. I am not impressed with the service MTN has provided and need this sorted out ASAP!