Online upgrade not delivreed due to out of stock

I decided to skip the hassle of going into a shop and rather upgrade online because it said on the website the phone I requested is in stock and would be delivered within a day. In the email confirmation, it said 3-5 working days due to a backlog. It has now been a week and when I called they said they will only be receiving stock again in a week after which deliveries will begin. This means it will be taking anything from 2 to 3 weeks for my phone to be delivered. If I had known this I would obviously have just gone to a store to upgrade. Instead, I now face chances of already going away on holiday before my phone eventually arrives. Vodacom must ensure their online store is updated continuously, it can't advertise in-stock and delivery in a day and then take two weeks or more.