Mica make you pay full price for items on Promotion

Went to Mica eastgate today to buy paint. The 20L white paint was on promotion but when I went to pay for it the system did not have the promotion price loaded. The floor manager and teller had no idea how to change the price and neither did the 3rd manager they called. At the end after 5 minutes of arguing I had to pay the normal full price due to their ignorance. Mica are ******* and their staff are ***********, I rather drive the extra distance and shop at builders any day.