Are you sure you are programming the correct lines? 078-080 seem high for what sounds like a small system ( company 2 had 3 sets and 3 lines). If this was on a 6 port expansion with a TM.... Lines 018-020 would not apply as those are usually reserved for T-1 channels ( except in VERY old software).Try adding the lines to a phone set to appear and ring and make sure you are programming the correct lines. If they are correct, try assigning (for a test) to table 1 (other company) and see if that table answers.If table 1works, there may be a problem in table 2 programming.

Good luck!

Ed