My 3yr old DD stays at her dad's 2 nights a week with an additional contact day (all court official). He lives with his parents and they refuse to discipline her in any way
When she's with me she knows what she is and isn't allowed to do. I'm strict and I make it clear I'm not a pushover. But EVERY week when she comes home she will throw tantrums to try and get her own way, she answers back "no" when told to do something and uses emotional blackmail (eg, can I have cake for dinner? But I love you. If you loved me I could have it. Nana gives me it) which is learned behaviour as her grandparents do this to each other and her dad. She also will get out of bed every hour to tell me she's not tired and wants in my bed.
Obviously all these things work at dad's house.
It's driving me barmy I never give in. She never gets her own way and after about a day and a half she clicks on it's just not going to work and settles.... Then it's time to go back and it starts all over again.
They have zero intention of adapting their behaviour and dad has made it clear he won't be intervening. I'm being made to feel like the worst mother in the world and some horrible dictator because I spend all my time with her correcting their mistakes and they get all the fun and cuddles
How is your relationship with her father? Have you talked to him about it?
Perhaps you could sit down and work out some consistent parenting rules that you both agree to apply. There is probably a limit to how much you can control what his parents do, but if you both take an agreed approach in other situations then that may help.
I think it would probably be more effective if at all possible to raise it with him as a suggestion of together establishing joint parenting rules rather than coming across as criticising his or his parents' approach?
I don't think you should try and make her father see her less, but some agreement of parenting ground rules could be discussed. She may be acting up because of the disruption or confusion or having been away from you. She is only three and it's a big thing to deal with when you're little.