Go to Court and request a very specific Order that you pick you daughter up from a third party and return her to a third party to avoid these confrontations. You cannot control what the mother and her family say when you are not present.
If she is in violation of the Court Order, take him back to that same Court for violating the order.
Lots of kids are vegetarians, being raised by vegetarian parents. I don't know that this is a problem unless she has weight or other problems.
I do notice you've posted the pick up/drop off information before and you received advice at that time - continuing to post the same question will not get you different legal advice.
http://www.askmehelpdesk.com/family-...ml#post1970898
If you want your child support amount to be reduced (
http://www.askmehelpdesk.com/family-...ml#post1969774) you have to go back to Court, prove changed circumstances and request a reduction. You can't simply stop paying OR pay a lessor amount.