Court orders and change of care.

Currently I have a court order with the ex husband in regards to our 3 children.
As he lives over 1 hr away he was to have them every 2nd weekend. He picks them up Friday at school pick up and I pick them up Sunday evening.
He recently got a job 4 weeks ago at the mines and will be away for 2 weeks and back for 1. We had mutually agreed to let him have the kids every 3rd weekend when he was home instead of sticking to the court order. He did say he would get paperwork signed to make it official through the courts, but we decided against it as it was only going to be between 6-12 mths. I know it was stupid now not to as we officially have a court order already.
Due to him been away he was only going to have them for 49 nights which is classed by CSA as minimal care. He’s telling them he will be have them more than 52 nights if he’s back in adelaide and there’s a student free day or public holiday. The 52 nights will bring it up to the level of care he’s currently been paying.
The dispute we have now is because there’s a dispute he’s sticking to the court order but the kids won’t be spending time with him as he’s not in adelaide. And he’s not adhering to the pick up time in the court order. He wants the pick up time we mutually agreed to while he is up at the mines. He seems to pick and choose now what part of the court order he wants to stick to and I’m at a loss as to what I should do now.
There are a couple of issues that are causing conflict but just don’t know where to go from here. We’ve been divorced for nearly 6 yrs and the drama still continues and it’s just getting very draining.