OK, so we all got off topic, its not really what he asked for - here send this!! 
Hello,
Thank you for your recent email, I'm sorry to learn of your desire to cancel the service.
The water fed pole method of cleaning is proven to last up to 4 times as long as traditional ladder methods, so a regualr clean is done quickly and efficiently, which can be seen to the untrained eye to be "splashing water about".
I understand from your email that the real reason for your decision to change is not the quality of service or the cleanliness of your windows and frames, not the regular and reliable service all year round, or the 100% guarantee of satisfaction and free re cleans if you are not happy with the initial clean but a case of someone else being cheaper.
I understand you may have financial difficulties and accept your decision.
Thank you for your valued custom over the last <insert number> months.
Regards,
Very good! How about this:-
Dear Mrs Custy,
I was surprised to receive your instructions to cancel your window cleaning and I was shocked to be twice accused of "simply squirting water" at your windows. You
know this is not true as you have your frames scrubbed and your cills wiped thoroughly every time I call.
Your windows dry to a perfect shine and yet you have the temerity to complain at the price of seven pounds! Well, shame on you! Shame on you for demeaning my concientious high quality service just to justify your feeling piqued in that I can do a job quickly and well. You obviously hate the fact that I am a successful professional businessman and that you are a stinking putrid pile of pus no-hoper loser thing.
You go to your neighbours cleaner; go on! And if he should fall off his ladder on your property and you are sued then I will support him in his claim against you; you have been informed that his method of cleaning is not the safest according to modern safety standards!
When you have your chimney swept do you tell the man with brushes to go elsewhere so you can have a child sent up the chimney? Well do you punk? (starting to foam at the mouth now
)
Halloween is approaching and if the Devil and all his hordes should egg your windows and bake them on with the fires of hell then don't you come running to me for a quality clean! You just stick with your luddite neighbours cleaner and pay your florin or half-crown or whatever makes you feel better you worthless, puerile, scum of humanity you! (gibber, baaaaaaah! gibber ...)
Oh .... and your hubby was obviously blind when he married you.
Yours sincerely,
Rant and Rave windykleen
P.S. To improve customer service would you please take the time to fill in the enclosed form outlining how you feel about our service. If you love our service then tell your friends... If you don't then tell us!