Welcome!
If I were you I would get a 312 KW v2 with the ST2555 movement. It is a very very good rep, the seagull is more reliable than the A7750, and it is cheaper. But parts for a Seagull are harder to source when needed.
However if you care more about the movement accuracy go for the v3 with the A7750 which is better decorated. Still not close.
Both movements are good movements, so at the end of the day it doesn't matter which you pick. It's all about preferences.
As for the TD not answering emails, it is Chinese New Year. So no one in China will be answering your emails. Patience is key in this hobby