If you have suifficient evidences you can still follow it up and ask about the status of your refunds to the blockchain.info customer service. After all, it's their grave mistake that makes you losing so many BTC and NOT your fault. They're responsible for this, rejecting your request of refund by nonsense reason such as "long time has passed" doesn't make sense at all, well unless they really delete the entire logs or data back then.
I guess that there's no other way to recover your bitcoin once it lost and moved to another address that you don't have access to. The only way is to enforce your right of having the refund from blockchain.info.
I have all the evidences and still have access to the same wallet within their site, they just waved me with the following response:
"Sorry but at this point we would have no way of verifying any of this information from you. The refund window for any issues related to that specific article has since closed."
Which is incorrect, since there is no problem to verify everything in the blockchain, and they never published a window to request refund.