MSANN I have been through something very similar. I can totally understand where you are coming from.
My children's father is an abusive man, he assaulted my children, my children told the school, the social worker, the police and it was their (2 of them interviewed separately) word against his. He made me out to be this emotional woman who put the words into their heads. Which I would NEVER do as they are my children and I didnt have a problem with their father until he abused them.
When you go to court (if it cannot be sorted out through your solicitors) ask for a CAFCAS officer who will mediate between the two of you. They will sit down with you both either together or separately and hear both sides of the story equally.
Although must say everyone on the legal side believed my ex until the last court case. Where he showed himself up to be a complete and utter prat.
He has telephone contact a number of times a week although doesnt use all those times, he did at first then the novelty just wore off. Get yourself a display phone, then you can get the children to answer it when he calls and you dont have to speak to him. Limit the phone calls to however long you wish for him to speak to them.
But do explain to the courts that you have been threatened in the past and your concerns for the childrens safety and your own, if you have police record numbers then all the better.
Like someone else mentioned keep a diary of all the calls and what was said you will need it in the future at some point if this carries on.
Take care and all the best.