So here's the framework, along with some comments.
We're looking forward to having you as our client, but before we begin, we want you to know that you have certain rights and we promise to respect these.
You have the right to a real human being on the other end of the phone. If your basement is filled with water, if your toilet is in rebellion, if your heating is cooling and your cooling is heating, you will speak to a caring human being, not an answering machine or an answering service when you call us. You'll be talking to a professional with a phone in one hand and a two-way radio in the other. And isn't that refreshing?
(Think of how you feel when you get an answering machine. Even if you're a small company, find someone to answer your phone. If that's not possible, create a Right that has you returning their call within a certain amount of time. In the age of cell phones, you can do this.)
You have the right to have us there when it's convenient for you. Ozzie and Harriet went off the air a long time ago. We realize that Mom isn't sitting home all day waiting for our technicians to show up, so we schedule appointments in a win-win way. We will do our very best to accommodate your busy schedule.
(By mentioning Ozzie and Harriet, or some other old TV show, you're letting the client know you've been around for a while – and that you're experienced. They'll like that.)
You have the right to purchase a service agreement, which buys you peace of mind and saves you lots of money. There is nothing like preventive maintenance when it comes to keeping things working as they should. An ounce of prevention is worth a ton of Tylenol.
(If you're not offering service contracts, then you should consider doing so. It costs a lot of money to get a new customer. Why not do your best to keep in touch with the ones you have as the years go by?)