Yes, unless you can prove the debt is the express responsibility of the other party. In most cases this would be proven in the form of official divorce papers from the court that specifically address that specific debt, otherwise the spouse is also responsible.
yes
yes
If you are not refusing to pay and you pay the debt, they would have no reason to sue you. If you refuse to pay a valid debt, they may advise their client to sue you depending on what state you are in and what the laws are there. Some states only allow original creditors to sue and not the collection agency.
If the debt was sold to a collection agency and the original creditor accepted payment AFTER the debt was sold, the money does not belong to them. If, however, you paid the debt and it was mistakingly sol after that payment, the collection agency can't try to collect. If you have proof of payment, forward it to the collection agency and deman in writing that they cease trying to collect this debt.
Yes
In Ohio, the statute of limitations for debt collection lawsuits is six years for most types of debts. After this time period has passed, the debt collector cannot legally sue you to collect the debt.
Yes, the term "charge off" does not render the debt invalid or uncollectible.
They can send you a letter, but they cannot sue you.
This is a misnomer. When an account is sent to debt collections, the collection agency does not typically own it. They are simply acting on the part of the lender or creditor. When judgment is sought on a bad debt, it is the lender who is suing. They are perhaps doing so through the collection agency and the lawyer they have under contract, but it is not the collection agency who is suing.
If the debt has not been paid on in more than seven years than no. Otherwise yes.
Sue them for wilful noncompliance and harassment.
If they've sold your case to a collection agency, they have been "paid" for your debt with the money the collection agency gave them for your case, so, no, they can't legally sue you - as far as I know.