Disgusting Discovery Insure Service

I logged a claim to have my car fixed and it was booked into the repair centre on 11 August. I requested car hire (I have 30 days on my contract with Discovery Insure) which was delivered on 13 August and needed to be returned on 20 August (or extended if required). On 19 August I emailed Mandisa (the agent I was dealing with at DI) to extend my car hire as the repairs were not finished. I received no response. So I phoned the DI call centre and was told the car hire had not been approved (so not sure how a car was delivered) and that a manager would approve it and it would be resolved and extended. I was then told by Mandisa (in writing) and my Discovery Advisor (in writing) that it had been extended. On 22 August - my car repairs were finished and I phoned Avis (and emailed them and Mandisa) to arrange that the car was returned and collected from the repair centre at 16:00 on 22 August. The call center said if they were late to collect - I just leave the key with the receptionist.

The car was returned clean and I re-fueled it. Now I cannot get my deposit back as Avis say the car hire was not approved, and Discovery has nothing to say - they just ignore me.

This is a lot of running around and admin - and I am out of pocket due to shoddy Discovery service.