Dear …
__(Name of Organization)__ has been offering __(type of service)__ for __(#)__ years now. We train all our __(customer service representatives/staff members/employees/etc.)__ to be both courteous and professional when dealing with customers. That is because we value our customers and take pride in providing them with first-rate service.
Something has come to my attention, however, that is very disturbing. I have had reports from several different sources now that on a number of occasions, you have made several inappropriate requests of our staff members __(and other customers/guests)__ here. Witnesses have informed me that on your visits to our office, you have approached staff members __(and other customers/guests)__ with requests that range form __(briefly list inappropriate requests)__ to __(briefly list inappropriate requests)__.
I don’t know what kind of business you are involved in, __(Name)__, but I can tell you that approaching our employees __(and customers/guests)__ with these requests while on our premises, is completely inappropriate. Therefore, I must ask that you immediately refrain from this type of behavior during your visits to __(Name of business)__. We run a __(type of business)__ business here and will not allow our employees __(and customers/guests)__ to be subjected to these types of solicitations from you or any other __(customer/guest)__. Thank you for your cooperation in this matter.
Yours truly,