Hi,
eBay/PayPal don't take feedback into consideration as it may have been left accidentally.
Try and call RM Customer Services and ask them to check the system and hopefully update with delivery:
http://www.royalmail.com/customer-service/personal-customers/contact-us
If there is the option to say you received a message from the buyer acknowledging receipt you can mention that, but again it could be they will claim it was meant for a different seller.
For an item of that value you should have sent by Special Delivery Next Day. Recorded only covers for up to £46 in the event of loss/damage. Therefore you won't receive compensation from RM as wrong method of postage used. 
Have you double checked the resolution centre to see if it's definitely an INR and not a chargeback or reversal?

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