Not happy with the third party excess recovery

I was involved in an accident 2 weeks ago. Front bumper of my car was damaged because the Driver B didn’t stop at the robot and on the scene he saw his mistake, I had a right of way now I claimed from my insurance and everything was sorted. I’m in the process of recovering my excess from my insurance and now they saying that my claim can take up to 3years. What I want to know is why does it have to take 3 years for my claim to be sorted ? Already I was not at fault and now this process is just adding more stress on me cause incured cost of which I was not anticipated.