Sasol Rewards Card switched

I've been filling fuel at thousands of Rands at a time and swiping my Sasol rewards card, with the intention of building up points to compensate for fuel trip. Yesterday upon filling fuel, I notice that a significant portion of my points do not reflect. Upon calling the call centre this morning, it seems like the card that I have is registered belongs to someone else. Not sure how/ when/ where this was switched, nor how the registered owner was able to utilize the points that I accumulated, if I have the card with me.