We don't know what you have bought, but every listing will state what payment methods are accepted.
If payments by an accepted method are being refused there must be another reason. Typical reasons might include:
- Your remaining credit limit doesn't cover the purchase.
- The listing did not include the shipping cost to China. If this isn't stated you won't be able to pay.
- Are you sure that the seller even delivers to China?
- Could the item be prohibited for export or import to China?
I suggest you start by checking whether any of the above apply. If not, ask the seller whether there is any problem at their end.
Failing that you may need to contact eBay customer support - but if you wish to give us more information about what you're trying to buy someone here may be able to make a better informed reply.
