Accessing iTunes purchased music on a previous Apple ID

I had an Apple ID which I used to purchase about 5000 tracks, all uploaded to an iPod, purchased in 2006. The iPod still works fine. However, my Apple Id was hacked 3 years ago, and I was unable to login to my iPad 2015 using that ID. I even had some money in credit on that account. My ICloud email was still useable, and it is what I used to upload my photos etc. I tried at length with Genius staff to overcome this

My question is: how can I access my songs when my previous Apple ID is not now valid. Is there a way I can use the Ipod to upload the items to the new ITunes?

Please advise. Many thanks