As an Asset Store publisher, you are not required to provide customer support on all your published packages, but you should consider providing at least an email address for users to contact you.
To add your support contact information to your account:
Navigate to the Info tab of the Asset Store Publisher portal.
Enter an email address under the Customer Support section:
Click the Save and Preview button to finish.
Note: Handle support requests from users in a professional manner. If the Asset Store receives complaints about a publisher’s conduct in handling customer support requests, they may review that publisher’s suitability for the Unity Asset Store, as stated in your Asset Store provider agreement.