Poor service

While attending the M Festival at Kyalami on 21 October we received flyers advertising the BMW Black Oil Service plans. On the same flyer, which I still have it states that as an attendee I would get a special discount on the Black Oil Service plans and that I would receive an email regarding such. No such email ever arrived. I've since logged a priority message as a BMW client to inquire about the discount, I received a call back a day later from a BMW representative who knew nothing about the offer. He promised to find out and call me back. Never called me back again. I then emailed *** and attached a picture of the flyers we received. They came back and quoted me the normal price. I rep**** and said that there is no discount app**** as per the flyer on their quote. That was on the 13th of November and I've not heard back since. As a BMW client this is extremely disappointing. To me it seems BMW is now ducking and diving the discount they've promised. I feel as per the adverti*****t I am entitled to the discount to use it when I need to take out the Black Oil Service plan. I don't know who else to approach as my dealership cannot assist as this is a BMW SA offer and BMW SA knows nothing about this and via two separate communication channels has ignored me. Poor service honestly.