Customer service is brutal, is super draining, and people reach breaking points. It’s gotta be tough on breeders who don’t have the resources/team around them to handle stuff like this. I remember the Gas Reaper guy basically tanked his whole company with a poor CS interaction. He obviously went way way further and broke some serious unwritten rules, but I think it came from
the same place.
Personally, I worked in restaurants for a while and think “the customer is always right” is one of the worst things about american culture. Customers are fucking terrible 
The guy was busy, stressed, and someone complaining over free stuff just put him
over the edge. Sucks for everyone involved.
OP you were a little sensitive and a little tattle-taley and the guy flipped on you. Two wrongs make a wrong in my opinion. Moving forwards I’d try to take some positives out of this interaction and leave with a big lesson - nobody likes a tattle tale. Nobody likes it when someone goes to teacher. My wife watches “The Bachelor” romance competition tv shows, and every season someone from the big group narcs to the main character about what another big group member did or said. The narc never ever wins the show.