Firstly, welcome to FlyerTalk Ashwini!

You haven't said when your flight was due to take place, but I assume some time after December 6th. I suspect that more details of your situation may throw additional light on this matter. e.g. the full routing involved

If all of your cancelled flights were with Malaysian Airlines, then they should offer you acceptable alternatives or, if no alternative offered is viable/acceptable, they should give you 100% refund. No ifs, no buts. But as has been discussed here extensively, Malaysian Airlines have treated their customers despicably throughout the pandemic. However I am wondering if you had connecting flights booked with another airline, and Malaysian are only willing to refund you for the MH sectors.

If all your flights were booked with Malaysian, and they continue to say they won't refund you the full amount, then you should dispute the amount with your credit card company. Depending on the consumer protection law law in the country which has issued your credit card, and your credit card company's own policy on refunds for goods/services not provided, that should provide you with your best option. There are several thread on this forum (nearly all on the first page) covering exactly this and related topics. If you read through all of these you should have a good idea of how to proceed. In my case, Malaysian offered me a voucher for the full amount, which I would have been happy to accept had it not been for the fact that the voucher could only be used on bookings made through a call centre, and call centres don't have access to the lowest price flights. My credit card company accepted my argument, rejected Malaysian's counter-argument, and I got my money back

If however you had connecting flights with other airlines, the matter may be more complex, so please let us know the full details, for a more considered response.