Write
[email protected]. I talked to Joy and Brent from over there.
If your old account was tied to an email address and you still have the email address, it will be an easy conversion.
In my case I only had a user name. I specifically avoided being tied to an email because I had lost email accounts in the past—for example, when old style hotmail shut down, and I didn't want my rafters account locked behind an email address I could lose.
If you have a situation like that they can still help you. But in that case make sure you tell them your reaction score if you remember it and case about. I thought to give them my post count but not my reaction score.
@Bluegrasskingreboot if you write them they can probably still get you set up too: see my situation here. Will just take more back and forth.