Am I liable for a debt sold to a third party collection agency - AL

The original creditor from 2015 sold my debt to a third party agency (actually, the debt was sold 3 times to three different companies). I am currently being sued for the debt. I have reviewed the original terms and conditions of the cardholder agreement and nowhere does it mention anything about the debt being sold to a third party and my liability thereafter. It does state that I agree to arbitration with regard to the original creditor and/or a representative of their company. Since the debt was sold to a third party and the Original creditor no longer owns the debt, do i legally owe a collection agency for which i made no agreement either verbally or contractually? Am I responsible even though the original cardholder agreement states nothing as it relates to the debt being sold to a third party and any liability theater? Please advise