Dischem sending me around and not providing what I wanted

Went to Dischem Strubbens Valley to buy Automatic Doom on their 2+1 promotions and was told I should go to Dischem Clearwater as the system shows that they have enough stock around 23 items. I drove to Dischem Clearwater and when I get there, I am told that they do not have stock and that they are not likely to get stock. When I ask how did the other branch advise me that there is stock in Clearwater, I am told they should have called to confirm stock and worse, the lady working in that department and the department manager at Clearwater confirmed that yes, the system shows stock is available but they do not have stock as it could be online. How was I supposed to ask them “Dischem Steuben Valley” to confirm before I went Clearwater? How should I know their procedures of confirming stock. They just wasted my time and petrol by driving around.