Very Dissatisfied

after much consideration I have decided to lodge a complaint about British Airways. On the 03/04/2026 I tried to book my seat online without any success. I then decided to get to the aiport earlier that expected by the airlines to book my seat at the check-in counter. The reason for my visit was to celebrate my mother's 90th birthday, a milestone in anyones life. I was suppose to fly from O R Tanbo to London on the BA flight at 21:15. Up until the time I arrived at the airport, I never received any notification about my up coming trip. A family member's friend who was travel;ing from the USA to the UK was advised that he needed an ETA which he app**** for on the same day of his departure and received it within 15 minutes. The security asked whether I have an ETA permit and in the past I would show both my SA and Italian passport without any incidents. The security gave me a QR code to arrange for this permit and said that it'll take about 15 minutes and not to worry any further. I must add that the woman at the check-in counter was exceptionally rude and unhelpful, these are the people that represent BA. By 21:00 I went back to the check-in desk and advised her that I still had not received any ETA confirmation. She then said that she would need to mark me down as a "no show" and I said to her that she cannot mark me down as a no show as I was at the airport ready to board the aeroplane. As far as I'm concerned a "no show" is a person who has not arrived at the airport at all. I had spent almost 4 and half hours at the airport with zero assistance. I then tried to get assistance from the call centre who were as unhelpful, it was as if everybody went deaf, dumb and blind, no one was prepared to help. I'm a pensioner and I've been saving up for this occasion and to top it of I've lost the full value of the ticket. I sincerely pray that someone in upper management reads this complaint