Thank you points

I received an sms from Jet in Oct / Nov 2014 to say that I have received 50000 (R50) worth of thank you points. When I went to the shop in Feb 2015 to spend my thank you points, I was told that it was taken back by Jet, because I didn't use them. I phoned head office and they said it was a promotion and I should have used my points. Nowhere in the sms did they state that it was a promotion and that the points should have been used by a certain date. I asked how was I supposed to know that, to which the lady rep**** I should have phoned customer service to find out if it is promotional points. It is not the customer's responsibility to phone customer care every time they received an sms. Jet should state on the sms that it is a promotion and what the cut off date is for the promotion. I expect Jet to credit my thank you card with thank you points or give me a voucher immediately.