If you have a visitation schedule in place that you have been following, then that is the part that has been worked out between you. If you want to change that schedule, and you two can not agree, then you will need to have it brought back before the court to have them decide the schedule. Based on what you previously posted, the courts are not likely to change the schedule since you were the one to suggest it and it has been being followed.
If you are having a problem getting the child support from him, I suggest that you quit contacting him at all and let the enforcement agency handle the situation. The child support will still be owed to you based on the schedule that has been in place.
On the rest of it…you could send a letter to the ex’s attorney stating that since if you are not allowed to contact your children while they are with their father, he will no longer be allowed to contact your home while they are with you. Or you can state one time during the day that you will allow a phone call to the children from him. Should the ex rethink the current situation with not allowing you to contact the children then you will reconsider your stand on this matter also. Realize that he is calling his attorney every time you call him. If he calls your home, do not speak with him. Let the children speak with him and then hang up. DO NOT PLAY GAMES WITH HIM, and do not argue with him. And realize that this is all that he is doing, playing games. When you do talk to him, try to be calm. State what you need to say and be done with conversation.
Let the attorney know in writing that you will no longer contact the ex and that from this point on you will let the Child Support Enforcement Agency contact the ex when child support is late. State the current amount that is owed and keep documentation every week of when he pays you and when he is late.
Let them know that you will cease all attempts to contact the ex but that they should be aware that this will include not contacting him for any reason. Let him send you an e-mail or letter if he would like to discuss anything. Let the attorney know, in writing that you would like to be able to work together to raise your children separately and if he is not willing to work together amicably then you will not be amicable either. Let the attorney know that he did agree to pay 1/2 the medical bills and give the amount owed on that, with proof. Keep records of everything. Do not put anything in the letter that you do not intend to stick to.
I know that this all sounds very harsh but if you had an attorney you would not be getting these letters. The attorney’s office would be getting them. All the disputes would go through their office instead of directly to you. Your ex is using that fact to his advantage. Every time you call, he can contact his attorney and tell them you are harrassing him, then he goes on about his day. Regardless of why you are trying contacting him, if he has asked you not to call his work, then you should quit calling his work. The children are not with him at his work, so the courts could see this as harrassment.
As far as the 401K is concerned, you may have to hire an attorney to get this distributed as it should have been. Or you can send a copy of the letter to his attorney every week requesting that this matter be resolved.