If the notes were absent when you made the buy, that's good. In that case the price is locked in and unless Coinbase tries some trick you're probably OK. 0.42 BTC for $100 is above the current price so you might make out alright. There is no cancel button AFAIK. You'll have to wait till the 15th and hope for the best.
I am agree with you .It's right according to our point of view.