The way they handled this sounds absolutely awful.How long have you been with the company for? Provided that you have passed your probation period, it sounds like a case of unfair dismissal. They can't base your dismissal on the grounds of poor performance, as you have been receiving good ratings over the past year; also (at least in the UK) I believe they should put you through a Personal Development Plan before they can fire you (provided you are not on your probation). They have to prove that you have consistently under-performed despite their efforts to help you get better. I would talk to a lawyer, get all the facts straight on what rights you have, and go back to them negotiating on a longer notice (4 / 5 months should be a reasonable timeline to get another job) threatening a law suit if they don't oblige.