portsmouthCSN - Passport interview long wait times?

Hi I've been waiting for a call back to arrange a passport interview for around 10 days now, portsmouthCSN seems to have a automated message when trying to call and when contacted the passport advice line they provided me another phone number to a booking line what told me they were unable to do anything for me unless i received a letter through the post. I've only received an email. I'm wondering if anyone has expereinced a similar issue and how long it took for portsmouthCSN to get in contact? Thanks