Firslty, as this may be the mistake of company who has made the RC (it is for the Traffic authority departments).
Secondly, at the time of buying the vehicle you must have given the relevant ids then it is their fault for which you can’t be held liable.
Thirdly, just make an affidavit stating as you are the same person in both the documents.
Fourhtly, then give them a representation to release the amount of insurance.
Fifthly, if they do not respond then please file consumer complaint in the District Forum of Consumer Protection.