Hello and thank you for using Just Answer,
Your situation is very unfortunate and not uncommon. I think the main reason you have had to wait for a response is because you may not like what a tax expert has to tell you.
Your personal liability will depend on the actual LLC. If a partnership, each partner is responsible for the acts of other partners when they act in the name of the business. That is, business, income and sales taxes are the responsibility of every partner.
If your partnership had changed to a single member LLC then you would need to get a new EIN. If the same people are still in the LLC then a new EIN is not needed.
Tennessee sales tax penalties will be based on the total owed but not more than 25% and minimum 15% for not filing. If the returns were filed then any underreported amount will be subject to interest.
The fact that your name was not on the EIN or the Sales Tax, would really only matter if the original LLC had dissolved and the other person was not in the picture at all. This is only good for the future though as you move forward. The past debt, especially for sales tax which is under the Trust Fund obligations would make the liability still open.
The steps you have taken thus far with the new management and the plans should protect you in the future. May I suggest that you ensure a separate account is set up for the sales tax collected separate from the business account all together.
I truly wish I could offer a different answer to you. The state will work with you and you do have options to recoup the money for the individual if it was used for their person gain and not used for business purposes instead of being remitted. Of course that would require civil legal action separate from tax.
Best wishes to you and thank you for your patience.