Thanks for the tip! Over the past week or so I had tried 2 different cards, both always failed, and I appealed too many times to count. This morning I bought a cheap 10,000mAH power bank (about $10 + shipping) from a supplier on Alibaba using one of those cards, and it processed successfully in about 15 minutes. As soon as that worked I went back to my 8x 280AH order with Dongguan Billion and selected "Make Payment", and my card was on the next page as an option. It did not "fail", went straight to "processing" status, and successfully processed 20 minutes later. Problem fixed in less than 1 hour this morning, after over a week of playing the silly "appeal" game, which never worked for me for some reason. Thanks forum!