I booked a ticket for my friend but she got to the airport only to be told that her ticket is invalid and a refund has been initiated. It was booked with avios but no information was sent to my email as to the cancellation or the invalidity of the ticket. She was meant to arrive in London on today 30th of December 2023. BA did not send any query as to why this happened, my friend was supposed to be with her heavily pregnant sister who is due to give birth in the first week of January 2024, so this is all so frustrating. Please what can I do to get a solution. I'm confused and frustrated.