Requested a refund - They denied the refund and won't let me on the flight. (KLM)

This was the KLM airline. I had rebookable ticket - ie pay a fee to rebook the flight until a few hours before the flight. I clicked request refund for just the one flight and apparently this means that i lose my full booking (Even though there was a flight in 6 months time in the booking). It was a REQUEST, I wanted to see the possibility of a refund, but if they reject my refund, I would still want to have my original flight, or at least be able to rebook it. I did not agree to anything else. The refund request didnt even let me submit any information (I thought I would be able to upload documents and give my whole story, I had decent reason).

They have now said they will reject the refund, not let me on the flight, or not let me pay the fee to rebook the flights. It is pure theft as they have not given me any service, or given me my money back.

Is this legal?