'Thank you for your prompt service upon a short notice.'
'It's is the first time I use this company and I have to tell you service was extraordinary. Thank you from the bottom of my heart it meant a lot to me that the arrangement get delivered on time.'
'Great customer service and the recipient said the flowers were beautiful.'
You won't be able to dismiss this by usual means (escape or click button), but you can close it programatically based on user choices or actions.