Used my car without Authorisation

I have a tracker on my vehicle which shows where and when my car has travelled. My vehicle has been used back and forth to the airport on three occasions and once to a council estate location unauthorised. They use a temporary location to store some of the vehicles 0.8 miles away before moving them to a larger compound 3.0 miles away. When I called them from abroad they skirted around the secure location questions of the temporary car park which is also located on or near a council estate. On return to uk last night I questioned the Hoodied Eastern European driver about the unauthorised use but he left me the keys and ran off. I have called day by day today to question them but was told the manager was unavailable and was giving me lip service. I have sent them emails and maps of the unauthorised journeys , my dissatisfaction about the mud in my car interior and have received no call and no contact from them . I must also point out they only insure the vehicle for £26000 worth of damage which is no good for my vehicle valued at £67000 there are lots of disclaimers in their terms and conditions relating to damage to the vehicle so be careful. I will be contacting trading standards if they make no contact with me.