No, I am not defending Sorenson. I just happen to understand how Videophone works and how they get connected, why connect failed, and so on. 70 months worth of my full time (plus) experience with VRS provider, that is where I learn from.
If you mean your registered number disappeared, then it is likely you haven't used it for 6 months, FCC now requires VRS providers to purge these numbers that have not been used in the past 6 months. It had happened to me and it not happen once, not even twice, more than twice with few of VRS providers! Maybe you don't know, the 10 digit local number is assigned by government sponsered agency (Neustar), not VRS provider.
Just FYI, I am done working for any VRS providers, damage done and I only could thank to John T. Yeh for trying to help Deafies by defraud FCC in the first place which result FCC lost trust with anyone involved in relay services, this includes Deafies, hearies, regardless.