BAD SERVICE

I've been contacting MTN call center non stop with regards to my tax invoice for september with no luck. I also sent an email to Xolile Sikhakhane which I believe is a supervisor. She never bothered to respond to my mail. At the call centre, the consultant that I spoke with provided me with the case number *** and advised that I should wait for 3 to 7 working days in order for me to be able to get my tax invoice. She also assured me that I will get my invoice in that period which it never happened up until today.