It was dm’s birthday on Friday and I unfortunately had to work until 3pm. We had arranged to meet after then (I only work 10 minutes away from the city centre!) in town to have a walk round the Christmas market and go for dinner, I double checked the plans with her on the morning and all was fine. Fast forward to midday and I receive a text at 12pm from dm saying she is now meeting my sister 12:30 instead and they are going for lunch but they ‘might’ still be in town when I finish at 3pm. Anyway I receive a text at 3pm as I am leaving work saying sorry but they are leaving town now to go home. I later questioned dm and she basically tried to blame me for just not being able to leave work in the middle of the day and said I had now ruined her birthday by making her feel bad. Aibu to think that she have just waited a couple of hours for me instead of cancelling our previously made plans? Sister is on maternity leave so she wasn’t tied to a specific time. Oh and Dm then posted on Facebook later in the day saying what a wonderful day she had had with her granddaughter.