POOR MAINTENANCE OF MY CAR JUST OPPOSITE WHAT DIRECTION GIVEN BY INSURANCE COMPANY

I have a car 2009 model , registered on November 2008. 35 days ago this car met an accident, not by my fault but it was hit by another vehicle from behind, and, unfortunately it was a big damage (I take this car on lease to own contract from a company.). When I gone to the insurance company I insisted for Nissan's company garage or the garage where the contracting company repair their cars. But my both requests were denied by the insurance company telling that Nissan's garage is only for 2010 models and the other garage could not able to do this work as it was a major repair, And that employee give reference to a garage assuring that those people are good for this kind of work.But, now almost one month is over(I handed over this car on Jul 3rd. They have replaced only one part i.e, dicky door that also a very old one. And the remaining parts they done welding and denting and they are intending to apply putty on all the parts to make it good.But they showed me a big list of spare parts on Jul-6. So, I gone to insurance company and shown the photos of the repairs. Then they called to the garage and assured me for a good work in my car.
In case, if this garage do this dirty work again in my car or if they do some damage to my car that is not noticeable what actions i can take? I am an expatriate and have no knowledge about the legal system in Qatar. Can any one help me?