My experience with Lange is exactly like yours and the funny thing is I’m from Toronto as well.
When you said you bought the socond one from AD in Toronto I knew immediately who the AD is and its a crazy coincedence that I had similar experience with them. Really really bad service. Disgraceful. In my case I bought a Rolex from them and it had defects. In addition they butchered the bracelet when they sized it for me. I noticed those when I took the watch home. I was back the next day with all the case stickers still on; didnt wear the watch at all. They refused to exchage it. Never went back to them again. Sales reps are super arrogant as well (except for a couple, theres a guy named David who is very nice). Since then I shopped from Raffi, Birks... much better experience.