Clicks refuses to give goods that i legally paid for

I went into clicks Meerensee and paid for my purchase. I received a sms from my bank that the transaction was successful . I was then told by the store that i need to pay again as the transaction did not go through on their side. I could not take my goods that i legally paid for and they gave me a blank slip as proof. No decline slip or transaction slip. I have to wait for my bank to reverse my money without having any paperwork for my transaction. Apparently i dont have to worry because it happens all the time. Even customer care could not assist.