You are not liable unless it is joint. They are attempting to intimidate you. Sole accounts are sole accounts.. no matter if you are divorced or a widow. Plus, I highly doubt he signed up online (with you knowing at that) in 1994.I would send a cease and decist letter. If they place anything on your reports sue them and buy yourself something nice.
Thanks for the support. I've wrote a letter today to the CC Services demanding proof that I had signed the original document in 1994. If they cannot provide this paperwork then I will write the cease and desist letter.