6+ weeks and Outsurance is still assessing our vehicle claim!

Hello. We’ve been through another week of back and forth with Outsurance agents and assessors. We were told last week Thursday that our car was written off, only to be told today that Outsurance has changed their mind and have unilaterally decided to use second hand parts to repair my car, despite the fact this will void my existing motor plan and remove the option of extending my plan (which we have done for the past 4 years). We’re now 8 weeks post accident. Outsurance, please can a sufficiently senior person contact the policy holder to work through this so we can resolve the issue?