Terrible customer/assistant interaction

I had just purchased some clothing for my kids and on the way out I noticed the promotion running, 'get a free watch after spending more than R350', so I returned to to the jewelry section only to be told that the 'terms and conditions' are purchases need to exceed R350 on non sale items only. I confirmed that the items I purchased were not on sale, even proved it with a receipt and hence would like the watch as advertised. The jewelry assistant mentions(like she knows it all) that I cannot decide whether the items are on sale or not, only the cashier can, and I need to go to customer services to return all the purchases and get 2 receipts that show items on sale on one receipt and one with the non sale items to prove the spend in excess of R350. Thought this was a bit of a backward step but agreed. As I get to customer services the queue is far too long for me to keep a toddler interested and leave, perhaps never to return to edgars again.