My mum had a similar experience where she went to sit down to find a man sitting in her seat as he wanted to sit beside his wife who had a middle seat. My mum got a steward and reminded her that she had booked this particular seat 6 months ahead. The steward suggetested he 'just take his seat' when she said she rather wouldnt the steward asked the man to leave and returned to my mum to say 'that he refused to move'.

I was raging when I heard the story. I love the 'contact the captain and ask him to offload by bags as I wont be flying today' is a great response and one I will remember if my seat ever gets taken.

A stupid situation nobody should ever be in. Emirates have to sort it out.