Claim rejected without proof

I used to love this insurance company until my car was involved in an accident and my claim was rejected, there are witnesses that never went to an accident scene, but could see that the driver was drunk just because he's taken long to exit the car after an accident. I wrote to their complaint department and came back with the same verdict and I have now involved the lawyers. What a horrible experience for a claim to be rejected without bit of an evidence...😞 😪