Hi Johnny H! Reading your posts I understand you're new to window cleaning.
From the look of it you've got here what I call a one hit wonder.
You arrange to clean their windows on a monthly basis but when you go back they make up an excuse because they don't really want a monthly commitment, just an "as and when" service. Here's how I deal with first time customers to ameliorate the problems of the one hit wonder.
1. Think carefully before replying to a request to clean someone's windows; consider:-
The state of the windows, the accessibility of the windows, whether it is in an area you want to develop.
2. Price it right - tell them straight from the start that you are not a fly-by-night window cleaner and that you run an insured and tax-registered business (if you are) or a reliable window cleaner (if you haven't got round to doing what you should yet
) and that you'll quote only after you've viewed the property.
3. Tell them your terms - monthly prices (and/or two monthly prices - if you wish to do that) and that you collect at the time of cleaning or they send a cheque immediately if they are not home.
4. Tell them that the first clean is always "double" (or whatever) because you need to get the windows up to scratch and that you have actually had (a dismayed look on your face helps
) people say they want a regular service and that when you go back they think they can put you off and mess you around.
nb I know when you're starting it's difficult to turn away business, but hold out for good business - you know you're worth it! (if they want a one off clean and you're happy to do it then triple the price or more based on the fact that it would not be fair to your regulars if they knew some one could just stop you in the street and get what they pay for all year round.)