Ok guys this is the situation so far:

She asked me out, after a lot of P&P and i set a day. "lunch together, then we'll see."

The day we have to go out first she postpone the time, then she text me saying that a friend of her made her a surprise, and she had not the courage to tell him she had an appointment with me.
I TExted then after a while ''i am sure you will find the best way to make it up right with me''

Then i chilled out around london the rest of the afternoon and night, having fun and thinking about the best way to punish this behaviour.

Freeze out for sure, but how? we work together and i have the feeling to make her win the confrontation if I just ignore her. I am looking for something more subtle, that really gets way deep and makes her understand how much she has lost.

Any suggestion brothers?

You work with her ? I'd just pass. I've dated a colleague in the past, that's a recipe for disaster...

If you're still up for it, wait until she asks you out again, live your life. Have fun anywhere else!

I know, that's not the perfect recipe.
And obviously i'll live my life. but i don't want this to go like nothing happened in her head.