What can I do if a transaction is declined?

Check the error code, then look to the API documentation for the next steps

In the event where a transaction is declined, you can use our list of error codes on our API documentation to determine what is wrong.

The payment state would still say "Awaiting Funds" but the substate would reflect "Payment Failed". 

For more information on states & substates, you can find them under our escrow API called "Get Escrow Status"