A: Good question and no worries, your contacts won’t be spammed.

In Acumbamail, if the same email address exists in multiple lists (for example, Subscribers and Users) and you send a single campaign to both lists at the same time, that contact will receive the email only once.

Regarding credit usage: At the moment of sending, credits may be temporarily deducted for duplicated contacts. Once the campaign finishes, any duplicated sends that were not executed are automatically returned to your account.