I have had the same problem.
Called round quite a few times just to be told she had no money or turning the tv and light off pretending she was out.
Lost count how many times i left a note and SAE.
The last time i was in the street i managed to get her to answer the door as an estate agent had called round to put the property on the market.
I watched him putting the sign up with her stood there.
I approached them and said would you like to settle up your bill for the windows.
She said she didn't have any money with her but if i called back next week she would pay. (yeah right)
The estate agent said it would look really good if i could clean the windows before he took the picture. The women agreed and i agreed.
I went back to the van and changed my brush on the pole for one i do the gutters with and went over to the house with just the pole (NO water).
The brush was minging.
I brushed all over the frames and glass with this brush leaving it a complete mess.
The estate agent looked just looked at me.
I told him that i had carried her for the last 4 months now with the same excuse and wasn't going to let in go on.
He understood where i was coming from and even he had a chuckle
I felt alot better after that and haven't lost a single customer in the street.
A couple of my customers mentioned it to me and thought it served her right.
Craig