You know what, most businesses really want to avoid having to fill positions. I.e. the cost of hiring someone new, after someone leaves, is estimated to be around $10k. If it's upper management, it might even be higher.

The point is, any business worth their salt will rather listen to an employee's reasonable boundaries, than have to go through hiring someone else.

Set some boundaries. Stop doing work that wasn't in your job description. Go home when your shift ends. Especially if you are in management, it's going to take a while to find someone to replace you, let alone train them. Most businesses would prefer to keep you, but keep you happy.

If they don't, walk.