Impossible to unsubscribe to the sms list

I fitted wedding dresses at Bride & Co Boksburg last year. Nothing wrong with the service, but I had to fill in my details before I could do a fitting. Since then I have been receiving promotional sms's for months on end! I am already married now and have ABSOLUTELY NO INTEREST WHATSOEVER in their promotions. I have rep**** STOP to EVERY SINGLE SMS, but come next week, i receive yet another one. I have mailed the Boksburg branch as well but received no reply. I would discourage people to go there purely because they spam you afterwards and there is no way to stop it. Please sort out this problem IMMEDIATELY!!!!