Doing nothing harms not only you but your daughters. They deserve to have a relationship with both parents. She is denying you this and the children. If she has in fact violated a court order, she must deal with the State that the original order took place in order for a new visitation schedule to be set up. Do not wait too long or the matter can be viewed as abandonment on your part - and the fact you continue contact by paying support will further to problem for you.
Fathers have rights too.
Don't miss that if it is important to you. Sincerely, Hope this helps.