Sounds like you're on the right track -- limiting exposure, not taking calls. Don't delete texts or email -- just don't read them. Save them for your attorney.
Don't forget to document everything he says or does in your own notebook, courts and lawyers like it when things are spelled out and clear. Call the cops if he continues to verbally harass you so you have that documentation as well. Police reports of some kind are good documentation -- means you're serious when it comes to following through and protecting the kids.
Heck yes to contacting your local or the national domestic abuse hotlines. They are the experts when it comes to leaving an abuser and what you can do to protect yourself further. don't hesitate to find out what it takes for a restraining order/order of protection in your area -- the cops may help you with this, if not they will know who you should contact about it.