I get to clear up the mess when things go wrong.
Sounds like the Story of My Life (the abbreviated version, that is).
But I guess what we're all wondering is:- is your colleague still around?
Meanwhile, being billed for someone else's costs sounds a bit off; has anyone contacted the company to query this? A simple mistake, surely?
I don't blame them for expecting payment before returning the kit, by the way. I expect they may have been caught out in the past!