Before this commit: Users encountered errors when attempting to unsubscribe a phone number from receiving SMS. After this commit: Now,issue has been fixed, allowing users to successfully blacklist numbers and opt out of receiving SMS notifications. It is due to a missing parameter when calling format method, followup of odoo/odoo@adfdf5ab33) task-3658380 closes odoo/odoo#152638 Signed-off-by: Thibault Delavallee (tde) <tde@openerp.com>