If it is Original Theme bugs then the theme Author 100% responsible to support you. But if it is for customization mistake then they are not responsible for any customization but you can request them to check what is going wrong. I hope them Author will be very happy to assist you.
I am very happy to know you are keeping patience. We are also expect the Author will be very happy to assist you. Author and customer nice cooperation is most important to fix any issue.
As I have told you if it is for customization mistake then they are not responsible for any customization. But If it is Original Theme bugs then the theme Author 100% responsible to support you. So, I think theme Author should at least to reply you to tell what is the matter.
If the Author didn’t reply at all then please Contact Support because if your required support not valid accordign to support policy then Author should at least tell you that customization is not a part of Support or something in their reply.