Account issues - songs purchased with old Apple ID
My computer has been upgraded to Windows 10 and when trying to sync my iPod it has come up with a message to say that 35 of my songs purchased from the Apple Store are no longer authorised to be played by my computer. When I click on 'Authorise' it comes up with my old Apple ID, linked to an old email address which I do not have access to, therefore can't change the password (and have tried all combinations of possible passwords). It wants to delete these 35 songs from my iPod (I don't even know which songs they are as it only tells me one song name!). How can I solve this issue? Apple for to charge me if they provide support, however I think this is an account issue.