The worst ***** when it comes to promotions to lure you in and don't care about their clients

I joined Virgin Active in August, was told they are running a 75% off promotion hence I joined, now I am owing over 2k in gym fees because I was never allocated the discount. I have called my medical aid that confirmed that since I am on vitality it should have been done as promised. They now expect me to pay this amount and I am sick to my stomach by the fact that I get unsolicited phone calls daily from them and as soon as I explain my issue the same consultants ask to "investigate " and never get back to me. Disappointed is an understatement at this point. I can't even access the gym cos they are not sorting it out and it's just dragging on.