crg

Mr. F. is correct. It's not really an appeal. It involved submitting the application with some documentation and massaging to support your contention that the 3-year bar doesn't apply to your circumstances because the pending I-485 meant you didn't accrue 181 days or more of unlawful presence. It could be as simple as including a letter.

An immigration attorney could write a detailed letter pointing out the relevant case law, precedent decisions, the Department of State Foreign Affairs Manual and nicely asking for them look at the application again.

Many ConOffs are very good at what they do, but some are just starting out and using hapless victims as guinea pigs. They're often the ones that are able to fix things that happened at the border once they get all of the facts.