How much later did you get to your destination? If you had stayed on the original flight and squished in you might have had a legitimate complaint for compensation on that flight. You removed yourself so that eliminates most avenues of compensation. Now the fact that the supervisor was wrong in the situation may entitle you to compensation but definitely not IDB compensation. The fact that you missed the dinner is irrelevant. You took yourself off the flight. So I would pursue the course of the supervisor and FA's did not follow policy which forced you to take yourself off the flight and see what it gets you. But if you try for IDB you will get nowhere. Maybe print a copy of the policy and take it with you in case this ever happens again. Then when the FA's and supervisor say sorry, no policy. You can say ah, but there is, and here it is, now remove the passenger of size.