I invited an acquaintance to my 40th birthday party who responded by text and Facebook saying her and her husband were coming. The pretty small party happened and they didn't turn up.
Over 2 weeks have gone past with no contact from her. So I messaged explaining that I was upset and that I was upset not because they didn't come but because they didn't bother to send a quick reason. The reply I got back said - they were sorry they were unable to get to the party (no reason given apart from - these things happen), that they didn't mean any disrespect and that she was unsure why I'd feel upset that they hadn't bothered to contact me.
AIBU to be upset over this. I find it really rude that you would accept an invitation and then not bother to explain your absence. But I'm hoping that others don't see it that way so I can move on quicker - I can't totally avoid these people.