The three important things which can reduce your support drastically would be having a knowledgebase for your website/product and having FAQ section and most importantly having a live chat feature through which your customer could talk with you live and get answers quickly. If you are looking for a free FAQ and chat plugins, Try Helpie FAQ and Helpie Chat which has powerful features and also a Pro version which makes it more powerful.
Just go to http://helpiewp.com/ and select the pricing menu on the top. You will have two options, one is the standard plan (6-month support) and the other is the 12-month support plan. You can choose the plan you wish and just select the Buy now button below of it. You can also see the Buy now button in the bottom corner of our Homepage. You can also try our free FAQ and Chat plugins if you are interested.
We have made a video tutorial on how to install Helpie and some more basics of Helpie. You can check this video to get a clear understanding: https://www.youtube.com/watch?v=L4aS0CsHhM0&t=
Yes. We have released a free FAQ plugin which you can insert at any of your pages. You can get it for free here: https://wordpress.org/plugins/helpie-faq/. Also, we have integrated FAQ with Helpie Kb where you can insert the FAQ in kb category pages.