Royal Sundaram General Insurance — vehicle insurance claim rejected

I have purchased insurance from this company. But they refuse to provide me claim amount after my car met an accident. They told me that you have mentioned wrong no claim bonus. But i would like to ask that why they are cheaking this detail after claim? Dont they inform me at a time of purchase?

Policynumber is vpn[protected] zero dep policy. I have met an accident on the date of[protected]. I have purchased the policy on the date of[protected].
I have purchased policy online by mistaken i have typed ncb 35%. And after 6 month when i have met an accident company told me that you have mention wrong ncb. They did not asked me for previous copy of insurance at the time of purchase, if they asked for that they could know all about the information but they did not asked. And at the time of claim they asked for all this things and regect my claim.

I feel cheating