Hi Gabriel,
If it’s only been a few months since you joined eharmony as a non-paying member, there is a good chance that your account is still up. Using your old account saves you from having to go through the laborious eharmony sign up process all over again, which saves you time and effort.
Once you become a paid subscriber, keeping your old account also allows the algorithm to go about quickly trying to find your best matches, some of whom you may have matched with in the past and liked, but you were unable to communicate with due to not being a paying member at the time.