WARNING...... This may contain VENTING!!!!

History... I have a 3yo son to Prince Charming, he has an 8yo daughter from a previous relationship (I have always accepted her, have even had the child in my care at DHS request for a little while, been a patient step-parent) I am always civil with PC's ex, despite the nasty things she has said and done. About 5 months ago, they moved to within 5kms of me previously they were 1.5 hours drive away, which i had always done the driving for visitation, back and forth. 

Anyway, yesterday I hosted a birthday party for Step-child. I invited a few school friends, FIL/MIL from PC's family and any relatives from ex's side that wanted to come. About 20 people came. It was the first time the families had met (so I discovered the next morning). We had a bbq for the adults and party food for the kids(two tables full of food), it was a pink princess theme (adhered too as much as possible without blowing my bank account) we had a few party games(which I sourced on the internet and made props myself) and the kids really seemed to enjoy themselves. I had a surprise activity planned for them... icing plain biscuits (a few different shapes, oval, square etc) and then decorating them with lollies, coloured sugar and the writing icing in various colours. It was a hit and was quite cheap to set up, the most expensive part was the writing icing. All the adults were amazed that it went dead quiet at a kids party as the budding artists got into creating their masterpieces.....All in all the day was enjoyed by all....... when all the guests had left, the birthday girl and mum were left, the birthday girl was furiously stuffing all her presents into a bag (her father and i gently suggested that she leave some so she had something to play with next visit but she wouldn't) next, the child runs off to her mum's car parked out the front and doesn't come back in, the mother just lets this all happen all the while waffling on about something totally off the subject, then tried to off load the child but child said she wanted to go home, mother then followed her daughter and left..... NOT a word of thanks, from either the mother or the child to me. I was shocked to say the least, not at first cause it didn't click to me but not happy now....... PC didn't even say anything and to top it off, he said he woud call the mother to have a word seeing I had put soo much work into the day, but alas he didn't.

That's my complaint over, I really don't know how to proceed in this situation, i think i'll just retreat and contimplate............