For old users who did not have trail period option when they signed up, the billing date is the sign up date. As for the newr users who has the trial period option of 14 days, the billing date is the 15th day after the sign up date when the first subscription charge is charged into the account. Billing date also changes when there are failed charges in the account . A ticket can be created also for the back-end team to request information of an account's billing date. You can email support@resimpli.com.