If it ain't broke, don't fix it.
Oh, ViaTalk, ViaTalk, ViaTalk...whatever you did in March, undo it. Everything was smooth as silk for years, then you did some infrastructure "upgrapes", and now we've been having all sorts of problems.
My previous dead-air issue was temporarily resolved. The fix applied has cause in-bound dead air plus the inability of IVR systems to recognize the key-tones when pressed. A ticket was submitted, and a fix supposedly pushed. We shall see...
I was really happy with VT's service up until recently (and, probably more importantly, so was my wife). Call quality, features, etc were all better than POTS, then you go mucking around with improvements.