What if ex wont do parenting plan or mediation?

My ex and i seem to disagree on parental responsibility. I am the resident parent.
What if my ex refuses to engage in a parenting plan and ignores any request for mediation?
What is my next, best, step?

What are the issues you cant agree on? Why is parental responsibility in dispute?

some examples would be:
* who is responsible for childcare costs on times when he has access
* Not turning up at access times
* altering access times without notice
* who else looks after the children
* diminished capacity to provide emotional wellbeing
* introduction of new partner against the child''s wishes
* who is responsible for pick up and drop off

to name a few...
all of the things that are in the parenting plan, which he refuses to do really:(

Bump

Who wrote the parenting plan, and how involved was your ex in the agreeing of it?

He won''t be involved in it at all.
i suggested doing it collaberatively.. He wouldn''t
I made suggestions- He ignored my correspondance
I suggest mediation- he ignores all messages surrounding it:dry:

So, this is a proposed parenting plan that you''ve written, rather than something that has been done jointly between you? How long have you been separated?