I only really use it for a consistent late payer (someone who hasn't paid there bill before the next clean on say 2-3 separate occasions, but fairly rare nowadays that i need to use it). I personally prefer to post it / pop it through the door as a letter, at least i know it will be seen and they can make their choice on what they want to do.
Its always my intention to try and keep the customer and the letter is always the last resort, I will have before I resort to using the letter leave a slip stapled to my window cleaned tickets on the first couple of occasions that says
Dear Sir/Madam
We kindly ask that you please ensure your payments are always made within 10 days from the date that your windows are cleaned.
We offer a hassle free Direct Debit payment system, just go to
www.impactcleaning.co.uk and click on the payments page for further details or to set up a Direct Debit with us.
Kind regards,
Impact Window Cleaning
If in the future it happens again after leaving a little reminder slip on a couple of occasions then I'll use the letter and its either sign up or i let them go.
Although i send out text reminders for payments, I tend not to try and deal with issues like this with text messages and e-mails as its easy for the customer to just say they didn't receive it, even when you know their lying there's nothing much you can really say.
Doing it the above way i feel I've tried my best to keep the customer and been fair with them.