I paid extra for a seat and someone who was bumped on an earlier flight was in it and allowed to stay.

I was trying to sit in the seat on my international flight that was paid for well in advance. ... As I was boarding the flight on August ** ****, leaving Dublin, the flight attendant lead me to my window seat, S*E economy Class **H. My son gifted it to me for Christmas and had paid extra for it. A woman was seated there so the flight attendant asked the woman to move but the woman refused. The attendant told me to "go sit down" and turned and walked away. The woman still refused to move. I had to sit in a smaller seat unlike the others where the man's head before me was about in my lap and the tray tiny. The woman continued to refuse to move. I was quite upset when I went to talk to another attendant. After hearing me out he went into *st Class to talk to someone else and when he returned he said I should certainly contact you. The woman in my seat proceeded to tell me that she had given up her seat on an earlier overbooked flight and was put on this flight as a result. The first Flight Attendant should never had let the woman stay in my seat. She did nothing to hear me out and try to resolve the issue. I had a rough time home. My seat was paid extra for well in advance.

It was paid for in advance to have a better traveling experience and I had to sit in an extremely uncomfortable smaller seat next to it.

This should be made right with compensation in the form of a reimbursement or ticket towards future travel.

I have flown Are Lingus many times. I expected a comfortable international flight experience comparable with what I paid extra for. I especially would expect better assistance from the flight attendants.