Get an updated and accurate Wage Assignment served on the present employer (which contains information as to penalties for non compliance on their end) and serve it on employer. If non compliance continues after that, you might consider pursuing them within the court for failure to abide by a court order.
The Orders in your case are the first step in determining your rights and the obligations set forward as to these issues. In the event that the Judgment does not contain specific language or other Orders regarding this issue, you will likely need to go to the court with a request to have the terms addressed as to the parties' ability to travel /vacation in future.
If properly presented and offered into evidence (includes authentication among other evidentiary steps), the information may be used. The rules are very specific and should be referenced though using counsel for this type of circumstance would likely be very helpful.
Locating his place of residence will help but his employer location is key so that you can have a Wage Assignment issued and served on the employer to obtain the funds owed. The local Dept of child Support services is a resource you can also use and then they can assist in trying to locate and enforce the orders.
You can collect support via wage assignment issued by the court and can also contact the local Child Support Services division for assistance in pursuing your ex for the sums and using enforcement methods via court to work towards him complying with the orders at issue.
I agree that the likelihood of a court ordering a live person for every communication is not likely to be a practical consideration and an alternative (Family Wizard is a common form) communication tool that documents the exchanges may be a better and effective option that a court would consider.
As part of your Declaration to the court with your papers it appears you are proceeding upon for a modification, you should include any and all facts that you have (including documentation, witnesses, etc.) as part of your case to the court to insure the element is considered as part of the hearing.