In our game, sometimes i think we can get ahead of ourselves. Ive been doing this job for some years (which ive harped on about in past), proud of my empire ive built up and proud of my job. Yet i still have to remind myself that at end of the day, our clients are our bosses, they hire us based on the services we have to offer. So if we get a txt for instance leave it this time as on holiday. Yep its a pain in ass, but they have every right to do so.
But we also have right to withdraw our services as well, its just getting that balance right.
When i switched all my trad customers onto wfp or when i take over a round as i am in process of doing. When i sell the idea of wfp to them and because im every 4wks, i do tell them their windows will stay cleaner for much longer. I can then tell, esp when speaking to fellers, they then ask if can do longer than 4wks. My response is simple. Its because i maintain them every 4 weeks that you will virtually always have clean windows apart from obviously birds fouling windows.
So i would have said same response to your customer and add that if you miss a clean you will soon start to realise.