I'd leave perhaps 10%....Perhaps....But I agree with giving feedback to either her or the manager or better yet both, so they don't just assume it's someone being cheap. Once in Hawaii we dined at a nice place and got very poor service, so I was inclined to reduce the tip accordingly. Only after we left did I realize we had used a discount coupon from the hotel, and therefore they probably just assumed we tipped on the final amount rather than the pre-discount amount. Fail on my part for not clarifying that the tip was a lower % of the gross bill, and the reason why.

I think that failing to submit the order to the kitchen is a pretty egregious error, considering that since many places have all servers refilling drinks and all servers running food to tables, submitting your order timely and correctly was pretty much her main (only?) job as your server. And especially at lunch when most people are on a tight schedule.