Hi,
You need to contact Apple Support somewhere along the line.
In iTunes go to the Store and then to the bottom of the page and click Support.
This will open a web page to start the process.
My UK version take me here http://www.apple.com/uk/support/itunes/
At the bottom of this Menu is Contact Support.
Click this then in the new Page chose the iTunes option on the right hand pane. (UK version http://www.apple.com/uk/support/itunes/contact/)
You now get led through a set of support questions.
Keep to the ones about Managing your Account until you reach the end and are offered email contact.
Explain the problem to them giving as much detail as you can. Dates and things you do know.
10:16 pm Thursday; July 10, 2014
iMac 2.5Ghz i5 2011 (Mavericks 10.9)
G4/1GhzDual MDD (Leopard 10.5.8)
MacBookPro 2Gb (Snow Leopard 10.6.8)
Mac OS X (10.6.8),
Couple of iPhones and an iPad