HDFC ERGO General Insurance Company Ltd - Vehicle Insurance trouble

i bought vehicle insurance from the hdfc gen insurance comp. ltd., policy number ******************* policy period **/**/**** to **/**/****. now the insurance company withheld my insurance policy with a reason of "non eligibility for no claim bonus (ncb) as per previous insurer". The company shows my previous premium as rs. **,*** and revised premium as rs. **,*** and asked me to pay the ncb difference rs *,***. when i denied they deny to pay any claim of the policy in future. if they deny to pay my further claims, i wanted them to refund my previous paid amount rs. **,***. they denied to pay even that amount. now that i took noc on ap**cl****. i bought jeep for rs. **lakhs and i could not process it with rta for this issue of insurance. it brought me mental trauma and heavy financial loss.