Ground staff who handled our check-in and later on the onboarding process before heading to the aircraft (employees of the airport, not the airline) were beyond rude in insisting we should hand in our paid-for cabin baggage due to the plane being full. Though that may be understandable their terrible manors and extremely poor service was evident for all to see. When asked why she was taking our bags specifically the female employee said it was because we had the cheapest fair which is a practical impossibility as we paid for both cabin & check in luggage. She also refused to give us her name claiming GDPR which obviously relates to guests/passengers and not operating staff. The supervisor of the process also claimed I was shouting at him despite my never raised my tone beyond conversational standards. Truly awful experience dealing with both these individuals who clearly haven't a clue of how to treat paying guests. Argumentative, plain rude and highly unskilled.