I agree, but build up a pattern of disruption. And maybe say the odd thing via email as well for evidence. For example after Friday you could email the ex saying something like
"I am disappointed that I agreed to change the court ordered Thursday night to Friday night last week, at your request, only to find that when I came to pick xxxxxxx up both your partner and yourself told her to tell me she didn't want to come. It is a parental responsibility, under the court order, to encourage a child to go with the parent. However this was not a court ordered night but an agreed swapped night so I am assuming you realise that was not a clear breach, but hardly builds trust for future arrangements. Wednesday night was however a breach of the order.
Please confirm that xxxxxxxxx will be with me, as per the court order, on Wednesday and Thursday this week. I also request an additional night on x day to make up the missed night last week. Please confirm if this is agreed.
I also confirm I will only be communicating over child arrangements by text or email from now on and not via phone calls"
With any luck she'll reply arguing that Wednesday wasn't a breach if xxxxxxxxxxx decided to come to Mum's by herself and not go with you. Which then confirms that she allowed that and allowed her to come home to her and not say to her - you're going to Dad's tonight, I'll text him to come and pick you up.
What you'll be doing then is building up evidence of all the frustration of the order and the ex encouraging your daughter to do something else. You also have the earlier stuff. So if next week goes ok and then something similar happens again then you've built up a few examples of what she's doing so it's not just seen as a one off or two off. It's a pattern.
Yes don't answer any phone calls.