What can I do when a card came up declined but customer said it went through?

[holdandhave]

I keyed in a phone payment and it came up as declined. I reached out to the customer and she said it was processed on her end. It wasn't but I don't know what to do. 

[VanKalkerFarms]

More than likely they are seeing the post on their statement try to authorize the payment.  It will show temporarily for a few days depending on the credit card company.