Legal action against seller for delaying RC book transfer process.

I made a full payment(online payment) to purchase a second hand vehicle in Chennai.My buying terms were very clear that i would need a current insurance (which he renewed) and transfer of RC book under my name. I currently hold the original renewed insurance certificate. The seller introduced me to one of his friend who he said would get us the RTO work done. Despite visiting this agent a few times, he has not completed the required RTO formalities and has now even switched his mobile off and is not reachable.Is it that if I fail to transfer insurance under my name in 2 weeks time, I will never be able to renew the insurance? Since, I have not got the RC book transferred in my name yet, I plan to cancel this deal and and take a legal course of action to return the bike and get my money back.After each payment, I messaged(WhatsApp) the seller stating certain amount for his Bike number has been done.Can this and online banking details be used to file a complaint?