I also have been unable to pay for shipping labels even though I have plenty of funds to pay for them and numerous backup payment methods. This also happened to me last week and I was told by support that it was happening to many people and it was a system-wide problem. They fixed it then but now its happening again. This time the only response I received was to clear my cookies and to use firefox or internet explorer. That seemed really generic, I still tried it and it of course didnt work. My orders are starting to back up and I need to ship these items... I hope you find a resolution soon too.
