Useless Airline my Partner was refused boarding because nut allergy on the day of flight

My partner and I arrived at the airport and she happened to mention she has a nut allergy and was immediately denied boarding our flight to Lisbon. No help and rude staff. It got worse after she wanted to catch up to me in Lisbon flew out on the same night on Emirates with no issue only to have her return trip cancelled by Turkish Airlines. No sympathy on what happened and no one cared. We are taking this further.