As an Asset Store publisher, you are required to provide customer support on all your published assets.
You need to ensure that you have an email address for users to contact you. This should be entered into the Info tab of your Publisher Administration account.
We ask that you handle support requests from users in a professional manner. If we recieve complaints about a publisher’s conduct in handling customer support requests, we may review the suitability of that publisher for the Unity Asset Store. This is also stated in your Asset Store provider agreement.