Beocom 2 line is busy, but it isn't!

Had a nasty electrical storm and phones went off.  Broadband still works.  Beocom  2 says line is busy but it isn't.  Also have 3 x Beocom 600, where bases are flashing red.  So same issue.  Does phone need resetting, and if so how can I do it?

You can try a power reset. Power off the base station, black box that connects to phone line. Power off all handsets. Power base station back on, wait 30 sec, then power handsets back on. That should clear that problem if its with the phones and not your line