Dont go back until its due again - if they phone up asking for them to be done, just say you cant fit them in now, as you had already arranged with them to be in their area. You also have other customers to clean for too, you cant drop everyone else just for them.
As you say you rang to let them know your coming, and they didn't tell you. Thats rude in my book.
I agree if they gutter guys make a mess of the windows, why clean up for them?