At what point does a deposition become harment?

A deposition does not become harrment. As long as the case is in motion, they can call you for appearance or deposition because you are apparently involved in the case somehow. "Commanded" is always the term used in subpoenas; I know, it sounds rude! LOL As for the appearance you cannot make, you need to continue to call the attorney and talk to him or his secretary or something to tell them you will NOT be able to be at court and they MUST make other arrangements with you for another court date. Sometimes it's hard to get them, but keep calling.