Changing of ID number on my Profile

I'm with MTN for more than 30 years on the same cell number. I have also upgraded my contract numerous times in the past. Recently, since last year, I am not able to upgrade my contract due to a mismatch between my ID number at MTN and my bank. Post 1994 ID numbers in SA removed the racial classification ie last 2 digits were changed. MTN refuses to change the ID number on their database. The bank has made the change. I have had numerous suggestions from MTN staff, from creating a new profile, to changing my phone number, to going into stores at various places, to asking my bank to use the old number. None of these work for me. Yet they still happily take my money from the bank - seems there's no issues there. I'm hoping someone in MTN has some knowledge on this subject and can help. Maybe I should just cancel my contract and go elsewhere.