Damn dude. Well complain to the pizza place. That's his fault for not counting the money when you handed it to him just like it would be your fault if you handed him $100 and didn't ask for your change within a reasonable amount of time, or worse yet, after he's already left your presence.

There's nothing to prove and he'd look stupid as fuck calling the police over supposed missing $5.

Likely, he probably got screwed out of some money earlier and is trying to make up for it after the fact or he spent it on something and needs someone else to cover it, that person being you.

And even if you were wrong, that's highly unprofessional of him to scream and harass you especially calling you back on your phone. I don't think a lot of pizza places will condone their drivers doing that, especially ones owned by a corporation who rely on a clean image. If the local store he works for won't do shit about it (return of the $5, a free pizza, etc.), threaten to call corporate and do it if they don't make an attempt to make up for their shitty employee.