Not a promotion

I recently receved an email and an SMS stating that I will receive 10% back on my next purchase on my credit card and then a1% on all other purchases made during the promotion period. I phoned the service desk to confirm that this was not a **** campaign and i was fuly informed by the agent that it was legimate and yes I would get 10% back on my next purchase. I duly made a purchase snd when my credit card statement arrived no 10% back. Logged a call with the service desk and after 55 minutes on the phone they told me they would get back to me. No respone so i phoned again and asked for feedback. I went to a Standard Bank branch and spoke to a banker who said they would look into it. I have sent copies of the Email and SMS and I eventually receive replies from both the branch and service desk that this was a competition and I hadn't won. This was surprise to me as nowhere had it mentioned this was a competition. I AM EXTREMELY DISSAPOINTED WITH Standard Bank and I am contemplating closing all my accounts with them