What do I need to get a transaction ID

I want to reactivate two blogs, including this one, that I haven’t had access to in about ten years. I finally contacted someone at my old credit union about getting a transaction ID but I don’t know who the charge would have been to so they or I can search for it. I don’t have the username or password, the email account no longer exists, and my phone number has changed several times. I just need to know how to find this/these particular transaction IDs.

The page I need help with: [log in to see the link]