In the cashless they normally take a sign before hand (just fill your name and reg no of the vehicle). Do you have the detailed calculations? Always Try & negotiate - ask for detailed calculations before agreeing on anything.

Had you also not submitted following documents?
1. Claim Form duly signed
2. RC copy of the vehicle
3. Driving License copy
4. Policy copy
5. FIR on a case-to-case basis

Note - If you are not happy with the insurer, don't accept anything or sign any paper till you know - what it is? and lodge written complaint. (Don't do anything verbally)