Well I let Benny escape and met him later at the legion HQ.
I got the platinum chip from Caesar and went into the weather station, when I wanted to leave (without performing the quest yet) they told me I could only leave once I completed the task.
I then killed the 3 or so legion members inside the weather station but when I tried to leave the fort they took away the platinum chip and said I would get it next time from the guard at the weather station...

So you can probably guess but that weather guy is dead and now I have no way of getting the chip back..
Are there any ways to force it back?

Reload the last save you have

I know this probably sounds stupid but I killed those guards inside the weather station at around 65 hours in, in the meantime I did some quests and now I finally returned (playtime 79).
All the while I thought the guy at the entrance of the fort meant the guy outside the weather station would give me the chip back so I thought ok no problem he's still alive.
Now that I realize he was talking about the guy inside I can't possibly go back or reload an auto save...

If you're on the PC there are console commands that can circumvent this problem. If you aren't the only main quest option open for you may be the NCR.

Yes I'm on PC, what command would that be?
It svcks that I have to do it this way but I simply have no other choice..


Btw sorry that I posted this in the wrong section

EDIT: Nevermind found it using fallout wikia!
Thanks for the help guys