Charged off is irrelevant for debt collection purposes.

That may be sufficient all together, the messages, the payment, and your testimony to convince a judge.

If you do not timely file a proper response, such as a motion or answer with affirmative defenses, they may get a default judgment against you. ...

Some of the facts you provide indicate there might be grounds for a valid lawsuit. Attorneys might be wary when told of implanted technology

It is legal to attempt to locate you including trying to talk to your roommate. Your roommate can refuse and tell them not to come back.

Your new attorney should handle this with the former attorney.

You need an attorney to look at the court filings to determine status. Your local legal aid offices or if the court has a pro per advisor.

It may be that criminal restitution orders do not expire. Consult with experienced attorneys in the state where this occurred.

Yes you can subpoena records. You can also consider setting a debtor’s exam and taking the effort to get her personally served.

The owner of the debt can sue you. If the owner is a corporation, then they must have an attorney except in small claims court.