False Advetising

I received an sms on the 1st of february from FNB saying that because I transacted on the FNB mobile app I qualified for 5gb of free data all I have to do is to purchase an fnb connect sim card from the branch or online within 30 days. I went to the branch on the 13th of February to purchase the sim card and activated it and even ported my number to FNB. 2 day passed without the free 5gb. then today I called the fnb connect call center to enquire about my free data only to be told that the promotion ended and the lady told me that she didn't understand why I wasn't informed when purchasing the sim card. I want to know why the false advertising to get us to be on fnb connect and can I please have my free data that I was promised