Swiss airlines is the worst company I have ever dealt with!

I need my money refunded in full!! This is by far the worst airline ever!

I booked my mother(who has been married 18 years to a UK citizen)a ticket with Swiss airlines to fly from Cape town(where she had been on holiday) to the UK on the 29th of November 2023 departing at 23:45 to visit for Christmas. She has flown to the UK with other airlines many times with absolutely no problems at all! However on the 29th of November 2023 she showed up at the airport to check in and After taking her passport and other documents the woman behind the desk at swiss airlines informed her that she needs to call her manager (apparently issue with my mums visa) and find out what they can do to accommodate her and that they might have to transfer her to another airline. Finally after 15 minutes on the phone she came back and informed my mum that she wont be allowed to board the flight because of her "visa" ( that's for uk immigrations to decide not a airline!) and that there is nothing else they can do for her! Now completely stranded at the airport at 24:00 (last flight of the day and all other airlines closed)with nowhere to go she had to take money from her pocket to pay for a hotel for the night.

After hearing how upset she is and crying, I decided to call swiss airlines directly to explain to them what just happened and the person I spoke to agreed that my mum was suppose to be able to board the flight since we paid for the seat and didnt understand why she wasnt alowed to either! I was informed that she will have to speak to a manager and find out if I could get a refund,since she missed the flight because of their company.

I just received a message from swiss airlines saying that I can get a refund but the refund will be made according to the fare rule and I will only receive barely 10% of what I paid for the ticket!?!?

What kind of a business let's you pay for something and then tells you that you can not have it and then says that they can not assist you anymore or give you the money back??? Only ****mers do that!!

Worst airline company I have ever dealt with!