Roam Mobility Customer Service Issues

I've been using Roam Mobility in Naples, Florida for over two years. I have the Roam Snowbird full service plan on my Apple iPhone SE. Lately, callers from Canadian Virgin Mobile phones have experienced my line being busy when calling, even if my phone is not in use. I tested this by calling my Roam number ([redacted]) from a local Florida landline, and the call went through fine. Also, when I call Canadian numbers from my Roam Mobility phone, I don't hear a ringing tone until the other party picks up. There seems to be an issue with the US-Canada connectivity. I hope that Roam's Technical Support can look into and resolve this promptly.