This courier got fired today...

Does this person know you've been fired yet?

It would be a fucking shame if you went in there for another "pickup" and accidentally smashed his so far down his throat he could chew with his arse. Terrible fucking shame.

you know what I would do? I'd simply head down there, find the bloke, and simply said "ah there you are, I no longer work for the (name of courier company) company, cause you got me fired" with a very serious face looking like you\re about to smash his teeth in.

see how he reacted, but adding a "why were you trying to get me fired?".

the simplest way is usually the best, especially when it's not breaking any law (e.g. smashing him up.