I bought some dogecoin on an exchange, that closed down its operations.
After 2 years of not seeing my coins, the exchange offered to transfer the coins to an address of my choice. I gave them the address, and the coins were transferred. I then sold some portion of my dogecoins on this exchange.
Now, I do not have any proof of purchase, as the original exchange has gone down. On my current exchange, all I see is that some coins were transferred from somewhere.
What would be your advice on this? How should I calculate the taxes?