So I had an email inviting DD to a party. It's a joint party and between the two girls they have invited five children. It's quite a special day out. DD very excited and I replied straightaway with a yes (replied to both mums). Then this evening I had a text from one of the mums saying - "sorry there's been a mix up with the invites ! DD has already promised to others. I'll speak to you tomorrow" AIBU to be livid? And what should I reply?