Phone lines not showing around office

[peter@rackliffe]

Hello we have T42S in our office. Last week we started having problems with putting calls on hold and having the line light up on another phone. We only have 3 lines and each shows on the display screen. Normally when we put a call on hold it would blink on all phones in the office, now only the phone that picked up the call shows.

A new problem that has started today; if someone is on the like and other phone is picked up it will give a busy signal since it tried to use the line already in use. Any help would be great, thank you.

Product Name SIP-T42S
Hardware 67.0.0.0.0.0.0
Firmware 66.84.0.105