TFG reward card

Today I collected my watch at American Swiss Liberty Promenade in Mitchell's Plain. I presented my receipt upon collection and just before I paid the cashier/ store associate she asked me for my ID. I thought its for the collection of my watch so I gave it. She then signed me up for a rewards card which I did not give permission. I told her I didn't ask for one as I have an account card and also I would appreciate it if she asked me. I gave the rewards card as I did not want any but on my receipt I saw that the reward card was still used. I'm really upset with what just happened.