Suggestion: When a duplicate bill is detected, ask the user if they want to merge them. Then prompt to choose which bill image(s) to keep - one or both, and select the correct data if there’s a conflict.
Some vendors send us physical bills on delivery, which get signed to confirm reciept in good order. Then they email us digital copies (unsigned) in case we miss any physical copies.
This would also be useful when a bill gets revised by the vendor.