Search contracts of sellyoursaas customers that are deployed + with open lines + about to expired (= date between (end date - SELLYOURSAAS_NBDAYS_BEFORE_TRIAL_END_FOR_HARD_ALERT) and (end date - SELLYOURSAAS_NBDAYS_BEFORE_TRIAL_END_FOR_HARD_ALERT + 7)) + not yet already warned (date_hardalert_endfreeperiod is null), then send email remind