There are a number of things that you have a right to do.
If you have an atty they can request the information and your stbx will be held in contempt. If you are trying to go to mediation then DO your part and let him show his colors.
I'm always thinking in terms of how do I protect myself financially .. that was going ahead and filing for temporary support. That at least got the ball rolling if he has a regular job the state will just take the money automatically I would encourage you to make sure you have that in order. It will help you in the long run.
As far as the kids and visitation I battle with this one .. document, document, document. When my STBX finally signed the agreement I wound up with sole custody .. I would say for me that was the right decision because he wasn't even going to the mediator in terms of cancelling his first appointment and so on.
Hell, he still hasn't signed off on the parenting classes .. can you imagine trying to wait for him to make a joint decision on the kids? If your STBX is willing to be that blatant in terms of seeing the kids and he's not doing what he needs to be doing then you can get it court ordered he take the kids. Maybe not over night however at least so you can have a large chunk of time to yourself. It is amazing to me that my STBX went 8 months without seeing his kids .. I can't imagine. My STBX lives with his mother and it's actually the kids choice not to stay and that IS in the parenting agreement. The nice thing about not having a parenting agreement is this .. you kind of have control over the situation .. I would never encourage anyone to keep children from the other parent. I deal with an active alcoholic who has a record and continues to rack up the charges. So sometimes I would just get a feeling that something was off .. I kind go with a saying sometimes someone else's rejection is God's protection. The kids went through an AWFUL visitation and that's when he didn't see them .. of course doesn't talk about it .. my kids are in counseling and so am I.
My STBX only has to take the kids 4 days out of the month and he can't even do that literally I think the time break down is 52 hours every other week and I'm lucky if he actually has them 14 hours .. they enjoy their time with their dad however .. they don't at the same time it's stressful. My kids are a older and the courts deemed them responsible enough to make the decision to stay or not based upon the fact that they had that awful visitation that they handled like adults. I deserve the right to have a life and that's something the kids and I have talked about openly because .. I'm not only their mother I'm a grown woman.
There are many options you have .. it just depends on what your situation is .. first and foremost he needs to take the kids .. secondly .. he needs to be paying child support .. I love how people who should be paying child support and just think that somehow they don't have to. I really don't get it. Anyway, big hugs and it will work out. If you can't afford or don't have an atty .. legal aide is a good way to go to get some answers.