Email support@lmgroup.au: a human reads it. Response inside 2 business days, usually faster.
On your device. There are no accounts and no cloud. Deleting the app deletes your empire: the economy is fragile like that.
Only for the optional reward ads. The game itself runs fully offline; your money compounds while you're gone either way.
Ads only ever play when you press a button asking for one, in exchange for a boost. Nothing interrupts play.
iOS asks for motion access the first time you tap the desk. If you declined it: Settings → INTEREST.EXE → Motion & Fitness.