besides, it seems maybe mom moved for the idea of maybe re-kindling things. However, re marriages work less than 10% of the time.
There are provisions on the order for under 100 miles and over 100 miles. It now falls under 10 miles. Check your order closely.
What you will need to do is determine the under 100 mile guidelines. Then, when you go to pick up the chiuld and she denies don't throw a fit...simply file a poice report with the local dept. Also, if she is leaving these messages or in person or by phone record the conversations. After a couple of months you will have ammo to file for enforcement against her, maybe gaining more time or even custody, even a more restrictive geographical restriction.. You simply have to document.
I hate to say it but you have to be calculating and not let her know you are doing this.