Chasing a sale vs trust

I needed to buy a new Macbook Air. Was sent to Somerset Mall iStore as Stellenbosch had no stock, but Somerset had stock of item I needed. Once there, I was told they don't have any stock of 256GB models left at any stores, only the more expensive one 512 GB. I declined to buy to more expensive model. Got home, checked online on iStore, model showed available at numerous stores in Cape Town area. I bought online and guess what? It was delivered to my home in less than two hours, from Somerset Mall iStore. Disappointing in store service, not great way to build trust with customers.