even had them sending back the correspondance email as their evidence for the booking which shows that it in fact that extra date isn't among the listed dates at all.

everyone else is losing their marbles (what few they ever had) due to repeated CoViD infections.

those thickos.

when you point it out, they are reasonable (or better). At the very least do a non-commital "oh, that seems like that wasn't a date you had booked, sorry about that," preferably a sense of, "oh fuck, sorry we screwed up."