Probably not a violation for which you would have a worthwhile lawsuit. Consult with experienced attorneys in the state where this occurred.

Unless this is causing problems for your mother, or if she has collectible assets, it may be unnecessary to do anything.

Research the court for the lawsuit against you and see how they claim you were served. Consider a motion to set aside the judgment if you were not...

There are several defenses to the lawsuit including the statute of limitations and that it was not you but the corporation who is responsible for...

Research online...

Research the court for the lawsuit against you to see if this is valid.

Assuming the time deadlines were met, yes. Consult with experienced attorneys in the state where this occurred for a review of the facts.

You can negotiate, especially if they will have trouble collecting.

Research the court for the lawsuit against you and see how they claim you were served. Consider a motion to set aside the judgment if you were not...

If you signed a contract to pay a certain amount, yes.