Authorize this computer / Deauthorize old computers no longer existing
I need help please. My old computers are no longer in my possession and apparently there are 5 devices already authorized to my itunes account but when I sign into my apple account page it does not show them or provide a deauthorize all button? I called apple support and was not able to get help - I want to authorize this computer to access all of my itune purchases - I am worried I am being blackballed by apple because I got really upset years ago when my computer crashed and apple was not wanting to refund all of my purchases - I hope someone can help me. Thank you