I don't think that katie will have know there was a bond.
The usual way these things work is the company won't have provided a contract before the start of training and will have only produced it after you have left.
If you haven't signed a contract they don't have a leg to stand on.
And for future ref if its as I have described never start training until after you have a contract in your hand. An email with the T&C's is not good enough.