ex wife puts kids on me - advice appreciated!

Hello, any suggestions appreciated for following problem.
I had a very difficult divorce 5 years ago. There are 3 kids involved, now aged 17,16 and almost 9. I applied for shared residence order, (if I recall correct term) and we went to family court and all sorted very quickly as ex was basically forced to allow me to have the kids about 40% of time.
Move on to current situation, normally you read here about ex wives not keeping to the contact arrangement by withholding contact but this is the opposite way around. She tells me when I am having them in addition to what was agreed so she can go away with her new partner. This creates chaos for my life as I never know when I have them. Not such a problem for the older kids as they are independent but a big problem with the 9 year old.
Of course I have refused but she just goes away!
I have written to her many times regarding sorting out a new arrangement but she does not reply as I think the current situation suits her in that she is ''in control'' and does not mind irritating me!

Hello David, welcome to Wikivorce.

I think you have two options here - stand your ground and stick to the times in the order. Or return to court for a Child Arrangements Order (which now replaces the previous residence/contact orders) that states your 9yo will live with you, and see Mum at agreed times. Your 17 and 16 yos are now too old to be made the subject of an order.

Thank you for response.
Cannot really stand my ground - she does literally just go away, so I guess it has to be the latter.

I have had a very similar situation which throws my work into chaos.

I dread the usual holiday periods as there is no guarantee that the RP will be there to receive the kids.

I did state that if it ever happened again, I would refuse contact going forward. Even though it would kill me not to see my kids, its just unmanageable when the scenario presents itself. You cannot live like this.