Dial Direct damaged my vehicle through their road assist service and they are failing to fix it

I requested a tow service on 18 March 2019 from Dial Direct (my Insurer) after the vehicle I was driving had a problem. The gearbox on my vehicle was damaged as a result of the towing service rendered by the insurer. The service provider accepted responsibility for the damage, but getting my vehicle repaired has been a nightmare. The damage was reported to Dial Direct on 30 April 2019, My vehicle was collected by the service provider for repairs on 27 May 2019 and returned on 6 June 2019 claiming that the vehicle has been fully repaired, but the gears on my vehicle are still not shifting properly. This has been reported to the insurer, but to this day my damaged vehicle has been sitting in my garage with uncer*****y on what is going to happen to it. The insurer is telling me they can do nothing about it as it's the service provider's responsibility to fix it even though I am paying my premiums to the Insurer and not their service provider. I am so DISSAPOINTED with Dial Direct, and unfortunately I am now stuck with a damaged vehicle for now. I would have appreciated it if Dial Direct had taken full accountability and made sure that their service provider towed my vehicle correctly in the first place and also made sure that the repairs were done correctly and to their clients satisfaction.