All Pending Orders Keep Getting Cancelled

Hello,

I have been having a massive problem with my selling account for the past 2-3 days (FBM), and the amazon seller support team have been absolutely useless with helping me fix the issue. For the past few days, every single order that a customer places from my account stays in the Pending status for exactly one hour then gets cancelled automatically because of "Payment Method Issues". Every single one for the past 2-3 days... I have already lost thousands of dollars in sales because of this. It seems that there is a glitch or a problem with my account that does not allow customer's payment methods to get accepted because this has happened repeatedly for over 10 different orders so far. In order to check if the problem was coincidentally actually from the all 10 customer's payment methods actually being invalid or if the problem is from my account, I did an experiment. I used my own credit card to buy something from Amazon from a different seller, and my card worked just fine and the order was accepted. Then, I tried to buy my own product on Amazon, and my payment method was immediately declined even though I used the SAME EXACT card that had just been accepted for the previous order. This shows that the problem is from my account, and seller support have not been able to grasp this idea and they keep telling me the problem is from your customer's payment methods which is clearly not true. How can I fix this issue to allow people to buy from my store again? And who will compensate me for the thousands in sales that I have lost in the past few days? I at least want to have the problem fixed as soon as possible so my sales can return to normal!