How did you submit payment, credit card or pay cash at a local bank?
In the chat groups I have heard of this issue, one solution is to start a new application in your ustraveldocs account and try to pay again. I don't recall if this ended up in a double payment, but I believe this resolved the issue. Also, I have heard of issues with credit card payment, but not with paying in cash at a bank and entering the receipt number.
these are the notes I saved from someone who started a new application:
"So after researching a little I clicked "start new application", this action closed out the old application and started a new form to schedule a new appointment. All the information was prefilled in from the last application except the MNL case number and DS160 confirmation number. I had to re-enter that information. Once I continued it goes to the Visa Fee payment screen, which I had already paid. Once I selected "credit card" the next screen showed that my payment had already been made and I owed no money. So basically the payment fee reciept # was attached either to the MNL # or the DS160 confirmation #. So I did not have to pay the fee again."