Swiftly checking lists: An american mess up :(

Took an engagement ring in for sizing. Was told repeatedly that the ring would be ready by Saturday 21/07/2018. Saturday morning phoned in to ask whether or not the ring is there and ready for collection and was told yes they have the ring and we can collect. We drove all the way to the store which is 30km away from us, we waited patiently for over 30 minutes to find out the assistant didn't check properly. So we had to drive all the way back empty handed. I can understand making a mistake once possibly twice but to have repeatedly failed at even the easiest task of checking that the ring was at the store is simply terrible customer service.