Checkers Cresta not getting it right

On my last two visits, the specials weren't correctly listed and the manager had to be called while it was sorted out. I use the express queue and have everybody waiting while it was sorted out ruining the express aspect. This wastes somewhere between 5 to 10 minutes each time. It is really irritating and to add insult to injury on the last event, I forgot my water bottle at the cashier due to the distraction of this. Get it right!