Apple genius

When in on 23 July 2020 and made an appointment to replace iPhone 8 battery on the 24th of July 2020. Booked phone in 14:00 and was tolled to return 16:30 to pick the phone up. When I got there they told me there was a software error that reflected as a hardware error and they sorted out then they said they dint have any batteries to do the swap with. Boggles the mind that you must make an appointment just to be told when fetching the phone that ow, by the way, we don't have any batteries.