Value those people who tell you the truth, not just those people who tell you what you want to hear.Pat Summitt
One of the most important aspects of providing support is the ability to be open and transparent with the information you are sharing… and knowing how best to provide that information.
Telling a customer the truth about a feature not working as expected, or perhaps not existing is much more valuable that find an obfuscated turn of phrase that is intended to provide an answer although not provide a solution. If you do not know, just say so!
Not knowing an answer is not necessarily a bad thing provided you let the customer know that is the case and also that you will find out what the answer is and get back to them with it. If you don’t find that answer, still get back to the customer with a response and let them know that, too.
Support is mostly about communication and building a rapport with the customers you are working with. These customers should know, or at the least be comfortable with, you will provide them the best, most truthful and complete answer you are able to.
Tell the truth… sugar-coat if you must but not so much you lost the customer. Going forward, you will both know you are starting from the same point and understanding.