Insurance claim

We recently purchased a second handed commercial lorry 4 months back which met with an accident a fortnight ago. FIR is also filed as the reason of the accident was rash driving of the vehicle that hit ours. We claimed the insurance. Our RC, FC, tax, licence, permit and insurance are upto date. We didn't knew the fact that the name of the insurance has to be changed. So we left it on the previous owners name. Now the insurance claim has been rejected by the insurance company as the name is not transferred. The name in all other documents except insurance are changed to ours. I believe the insurance is for vehicle and not for the person whose name is on it but yet our claim is rejected. If the name transfer in insurance is so important, we shoud be informed about it by someone when we paid tax or something but that didn't happen. Now without any knowledgeable mistake of ours, we are suffering. Is there any way by which I can approach on this case legally?? We pay a huge sum for insurance every year because we believe it wil be of some use when we need it. Now that we need it, they say they can't help us just because we were unaware or uninformed about the fact that the name that has to transferred in first 15 days of d RC name transfer. Can someone please suggest me in what I could do on this case. It would be of much help if I could get any information about this. Thank you.