The reason I put the seatbelt sign on and expect people to be securely seated is because there are, will or may be conditions which require their use to ensure the safety of the passengers.
Flybywire - Your job is check to make sure that the cabin is secure. You did, and you also, I my opinion, correctly informed the flight deck that the "secure" status if the cabin had changed. The ball is now with the flight deck. Leave it there - you've done your job. They will then choose to hold, land or go-around, as appropriate and you will also probably be informed as to their decision and any of any other actions they require you to take . Leave it at that and I'd suggest that any "bollocking" comes from others (like your company or the court system).
Lembrado - An aircraft is not a democracy. If I say sit down and secure your seat belt, you do it. If you need to go to the toilet, you will either have to wait or soil your clothes. There is only one Captain on my flight and that is ME! If you choose not to obey my order, I will call the police, I will ask them press charges, I will attend court, my company will not accept further bookings from you. This is because you have not only endangered yourself but more importantly, the others around you by your action.