PSA: Spoof Caller
A scammer is spoofing a legitimate USPTO number (571) 272-6500. They call and say they need to talk to you about your application. When you say, "Shouldn't you be talking to my attorney?" they say, "No, we can't recognize the power of attorney until we have more information from you." Eventually, of course, it gets to the credit card information and payment part.
Please note: if you have a pending trademark or patent application, and you are represented by an attorney, the USPTO will not contact you directly.