Telefonnummer hängen an der Adresse und sind daher in der entsprechenden Tabelle gespeichert
SELECT cus.id_customer ,addr.id_address, addr.firstname, addr.lastname, addr.phone, addr.phone_mobile FROM ps_customer cus LEFT JOIN ps_address addr ON cus.id_customer = addr.id_customer ORDER BY cus.id_customer, addr.id_address