It is a pity you didn't come here before making all those phone calls. If you still had access to the old email address you could have just addd that to Paypal and the money would have appeared in that account straight away. If you did not have access o the old email you should have called Paypal straight away and asked them to refund then you should have messaged tthe buyer once askng them to pay again using the correct email address. Chances ar you would have avoided a neg and a lot of wasted time.

I still have email addresses that I haven't used for up to ten years or more but would not dream of removing them from Paypal unless I reached the maximum 8.