mtn treats their loyal clients like ****

I have been with Mtn for over 15 years, my handset upgrade is due 1 november 2015! Mtn has a special whereby if you upgrade before 31 october 2015 you get 30gigs data for a month! I then went into a store to get my upgrade 12 days earlier to receive that special!..the consultant told me to email the credit department as they can't contact them via a phone,i then did and a week later,no response,i then was given the consultants personal number because they don't answer the branches phone! I am even prepared to pay in a months installment to get my upgrade but due to some idiots working there,its not possible!! Nobody answers their phones,not even customer care! I then phoned 808 and the consultant told me to tweet Mtn as they will reply immediately! WTH???...what kind of business are they running??..I got my upgrade earlier before with no problems,i don't understand what the hassle is now,i have emailed,phoned,tweeted personally gone into the store and I am still without my ugrade! I have so many reference numbers that I can't keep up! PLEASE HELP