Hi,
Actually we do provide only sales support via live chat, and that is instant, as we do not want any confusions regarding the tech tickets, so tech support is provided via tickets, email, phone and if any emergency then live chat sales can communicate to the tech department too, so 15 minutes guaranteed response time means that if you open a support ticket, our tech department will start working on it within 15 minutes, mostly our tech team response time is within 5 minutes, still we guarantee 15 minutes as we do not want anything that can be wrong.
Thanks for your update and question.
It is great that you have well-planned about the support of your customers/users. It is very good that you are providing support via almost all the way namely tickets, email, phone as well as live chat support. Hope you will continue this type of support.