I don't understand how these guys get away with collecting... Most of my customers are in when I clean their windows, or they leave me with a cheque hidden in the garden. But the odd ones where I have to go back, are always like 'ah so, how much do I owe you again?' - basically, if you're a bogus collector, your not gonna know prices etc... unless they steal a diary from your van.
Best way for us to eliminate this problem is by telling our customers, perhaps even write them a short letter, explaining that only you as the window cleaner will EVER collect money.
Unfortunately there are these little toe rags in every trade, and no one is safe