Stock on the shelf can't be purchased

Went to clicks comaro crossing on Sunday, no stock of preg omega plus. Returned today and still no stock, I decided to purchase the clicks brand of preg omega plus, however I was told it's not picking up on the system. I was told to drive to another branch. Absolutely useless as if something is on the shelf why is it my problem that it's not on the system.

Can't believe a national company has something on the shelf but I can't purchase it, and I had to leave without it, as no one could put it on the system