You’re not wrong but a lot of people do just that with the implied threat of not paying. This threat is empty because in the simple case of requesting a service and a quote - then not paying - this is more than annoying - it is illegal.
I’d never file a complaint if there were any gray area but in the most brazen case I’d go to the police. We often have the electronic or paper correspondence for the transaction and then the next step is to get a police officer as witness to confirm who was involved and that a service was rendered.
This isn’t bravado and I don’t think this is in general a good idea - you can’t throw the police at customers because they are behind payments and everybody is an asshole some times so I’m okay with letting a lot fly - I am thinking of that minority who set out to rob you from the start - I do think we should remember a big part of the reason why the police exist is property violations.
If this is not true by implication we believe the police do not work for the working class.
If the police cannot look into it because some areas have so much serious crime they have other priorities then the other option is to sell the debt to a debt collector.
Most residential I do not use a wfp. I’m sure it can be much easier much of the time for many. Many places can do the outside from the inside the way many windows are. Old fashioned way is pretty easy to me. I clean the frames well & all around the window. I don’t waste time either. Much of the time they see what all I’m doing at some point & are usually beyond pleased with what all got clean, the speed, how perfect the job just was afterwards. No water everywhere from wfp & dirt flowing around. I charge more on the high end. I actually get extra without asking quite often because of how I do everything. Most people I come across just want it done right. When they get more than what they expected, definitely nothing to complain about. They just tell all their family, friends, & neighbors. Leave good reviews, etc. .
You will always have those people that are just real cheap looking for the best deal, or just trying to talk you down for a better deal. Nicely stick with what you charge & if they walk away basically, let them. They can can go with the cheapest in town. Not common at all that I see. Once every year or 2.