Adds one contact to a KlickTipp account by hand, with its contact-field values in the same call -- the Add Contact screen of the app. Takes an email address, a mobile number, or both. The contact is subscribed at once, through no opt-in process and without a confirmation message, so it is reachable by the next mailing; automations may start. Only for addresses the account may write to by hand: an address that unsubscribed is refused, the account needs the add-contacts permission, and the call counts against its daily import limit. An address the account already has is updated rather than added twice, and the values given overwrite what it held; the answer says so in alreadyExisted. An unknown field ID or tag is refused, never skipped. Use subscribe-contact-via-opt-in-process to let an address opt in through a named process instead.