Welcome to the site.
First off, good luck with the divorce. I hope that your ex starts being more reasonable soon, but just in case, are their lawyers involved? Some lawyers are good and work for the best solution, but some are a little more concerned with getting the best deal for them... these are not the same thing.
Try to keep all communication in writing about the settlement this is for many reasons. First, there is written evidence of what was agreed, memories are not perfect. Secondly, if communicating via email or letter you can take time to breathe and consider a response which will help the conversation stay on topic and be less emotional. I say less because both my ex and I have been known to reply straight away to messages and so damage communication.
Secondly... CAMP! You must camp with us. And, to be honest, your kids will be having too much fun with their new friends to bother with their devises. Also, at SWK camps we are all together and everyone will be happy to help you set up if you just ask. And even when you don't ask, they will offer. We are a nice bunch, strange, but nice. CAMP you will love it.