Stop PRL from automatically updating

I have a Digi ConnectPort WAN running near the Canadian Border, but on the US side. Every ~6 months the PRL seems to automatically update to a latest version. As a result, the digi modem starts communicating with a Canadian tower and incurring roaming charges. To stop this, I manually revert back to an old PRL file which blocks roaming. Is there anyway to lock this PRL into place so that I don’t have to revert back every 6 months?

Which carrier is being used? Some carriers require an automatic PRL push which cannot be disabled.

The modem is using Verzion.

This is a question for Verizon. As I understand it is a requirement of their network to push down PRL updates periodically. Perhaps you can get them to disable this on your account. Else I have never heard of this being a problem.