What can I do to get my visits if I have 50% custody and scheduled days but she isn't letting me see her?

Obviously is you live in different states the 50/50 residential arrangement (I assume that's what you mean by 50% custody) can't work. However, you are entitled to whatever time the parenting plan gives you. If she withhold the children, you need to file a motion for contempt. You also need to file a petition for modification of the parenting plan to account for the fact that you live in different states and 50/50 probably doesn't work unless you're right at the border between the states. 50/50 plans don't work if you're more than about 30 minutes away from each other. I suggest you get a lawyer.