Wrong Adress on invoice and statement

I am very disappointed in MTN consultants it's been more than 5 months now trying to change the address on my invoice and statement. I've been calling a lot of times but it always come back with the wrong address on email. I'm even tired of calling them anymore because it seems like they can't do the right thing. They made things worse in June as the adress on my invoice was WRONG and INCOMPLETE! It's written like this: 72 Mitchelle Berea Hillbrow 2198 I called I'm again to alert them that it's WRONG and I was promised that they will rectify it. I always give them the correct address. I'm tired of calling for one thing that is not getting fixed.