It sounds like you have several issues going on and it very well could be hardware related, but I would have to ask how much troubleshooting has been done? I have seen in the past where accessing a line says "access deny" is caused by the line not registering the proper voltage from the carrier. The SBX is very sensitive about this according to tech support. The IP phone issue could be caused by many different things such as carrier loss of signal (on either end), IP conflicts in the network, improper networking in general, bad VOIP board, corrupt database, old software etc... Has the system experienced any sort of power surges? Have you recently changed carriers or has the network settings been changed at some point? Your vendor may have checked on all of this and more and should be trusted to lead you to the best solution, but if you don't feel confident in their solution, maybe get a second opinion from another authorized dealer. One thing you said "So some parts of the programming were saved and just had to be turned back on", tells me that something happened to the database. It should have been reinitialized and reprogrammed with a good backup or from scratch and it sounds like this wasn't done, but maybe it was. I'm sure someone else will chime in, but this is just my 2 cents. Good luck and let us know how it turns out!

"I thought I was wrong once, but I was mistaken"