That's just horrible- their lack of communication after you called ahead & let them know all that you could...it's just bizarre. Maybe they had a bad experience recently with some similar situation (like an attempted hold-up?), that's all I can think that would explain their horrible treatment, but to leave you waiting instead of communicating was absurd & unprofessional on their part. Very sorry for the loss of your dog, & especially that they allowed him to suffer.
Years ago I lost my large male Doberman in a similarly sudden manner- I came home to find him really "out of it"- turned out he had liver cancer- quite large but wasn't detected until then because there were no symptoms & Dobies have such a deep chest- there was nothing visible. I got him to the vet though to help him pass- it was nothing like what happened to you, leaving you calling & waiting outside for their assistance.![]()