Re: SWTOR: Companion not available
I've found a couple of bug reports on it and other chapters as well. Some of the solutions I've seen are to log out, then re-log back in.
If you cannot reset the mission try to use the /stuck command like try to go back to the area of the mission. If you can't use the play button you should be able to fly there manually via the galaxy map.
Other things I found would be to go the area if you can and use the /stuck command which may force a reset.
If all else try to run a repair:
Non-Streaming launcher - Log into the launcher but don't click Play. Check for small letters "ST" in the bottom left corner. If this is NOT present, With the new launcher after login , select the username pull down on the top right and select settings, then press repair.
Streaming launcher - If the letters "ST" is present, close the launcher, right mouse click on the game shortcut, select open file location and delete the BitRaider folder. Then start the launcher.
While this may not fix it, it wouldn't hurt to try.
If you have submitted an in-game ticket they may be able to reset it or get it to continue. I know that due to the release of 4.0 they're ticket volume is much higher then normal and it may take up to a week or longer for a response, just depends but if the above doesn't work then that would be only way other then the devs to release a patch to fix the issue.