incompetence

i was at the supermarket and was just finishing at the checkout, i.e. had put all the groceries into the bag and given the cashier the money, and it went downhill from there. she started talking with a colleague about something or other and when the machine chimed at her, she just clicked ok and then realised she hadn't actually put in my money. she was apologetic but we had to redo the whole thing. so i took everything out of the bag, gave it back to her, she did her thing...and came up with another amount than the original one. from 16 euros we were now at over 20. well that wasn't normal. she looked at her screen, looked at my groceries, tried to figure out where she'd made a mistake, deleted an entry, but we were still above 19. 

i could see this was going to take forever so i asked her to just repeat the entire operation once more. she argued she couldn't, as that required her supervisor's authorisation and would take time. i said that was fine. her supervisor came over, she explained the whole thing to her and the woman said there couldn't be a mistake as the machine automatically calculated. my point was that i didn't much mind how much it actually cost but would like to know the amount was correct and would thus appreciate it if the whole operation could be redone. she acquiesced and for the second time, i took everything back out of my bag. the final amount was 22 euros! at this point, having made sure it was done properly, i just paid. the way i figured,  a 6-euro item clearly hadn't gone through the first time. but still, 3 check-outs and 3 different amounts, ridiculous. not to mention the time the whole thing took...