MTN Womens' Day Promotion - Spa Voucher - Impossible to Redeem

I received an email from MTN promising a spa voucher if I upgraded my phone. I did upgrade my phone but no-one at MTN La Lucia seemed to know anything about the voucher but said they would find out and get back to me which never happened. I went in for a 3rd time yesterday to query this, and this time I was told to go to another branch or phone the call centre. Why should I have to do that when I'm in the store (no other customers around)?? Why didn't the consultant make the effort to find out for me?? I've been a client of MTN for 30 years and have just spent thousands of rand on this phone but it seems after the sale is made no-one cares. Disgusting service besides the fact that a promise was made and is not being kept!!