I cleaned windows for 10 years. I built my own round the hard way, knocking doors after full days on the pole, chasing payments in the evening, watching canvassed customers melt away after one clean.
When I moved into online marketing, the fix was obvious. Homeowners search for window cleaners every single day. Put the right advert in front of them, confirm the job properly at the cleaner's own price, set up the payment before the first visit, and you get a customer who actually wants the service. Those are the ones who stay.
That is all WCL is. The system I wish had existed when I was on the tools. Every customer we hand over is confirmed the way I would have demanded for my own round, and if they do not make it to a second clean, you get your money back.