Technically, this is not a communication tool to get in touch with you directly. It can negate the need though, which is often more valuable. Having an online reference guide available can save your customers a lot of time and stress.
We use Help Scout Docs to keep our eCommerce user guides easily searchable. We especially like Help Scout as it allows us to integrate a lot of our customer support into the one platform.
We can place a support button wherever customers may find it particularly useful. It is also given prominence on our contact page. Have a play and let us know what you think.