I contacted my credit card company first to make sure the problem is not there. They said all is good, must be an Apple issue.
Next, I followed your links. Got a case number and phone number to call.
Called and explained to a guy the problem. He walked me through the procedure. Still didn't allow me to add money to iTunes.
He sent me over to iTunes Dept. I had to explain the whole problem to a different person. She put me on hold for 11 minutes. Told me the case was sent up to the trouble shooting dept and for me to allow 24 hours and they will email me a reply.
She also told me she never adds money to her iTunes using her device, she goes to Apple.com and sends herself a gift card. So... I will wait 24 hours and see what sort of reply I get. Really though, this is way too troublesome just to add $10.
Anyway, I'll let you know how the next step goes.