You're still providing excellent customer support I see.
Thanks for the time you spent with me on the telephone about your site...I think you have a potentially great success story here.
...having found your service by chance, we've been completely happy and pretty surprised actually. You offer a lot of features, with a very reasonable & logical rate system. ...How much your service will help is possibly beyond your understanding, but I'm sure you've heard that from other people using your service.