You can block a community member on Legiit from communicating with you and also purchasing from you.
To do this, you can navigate to your conversation hub, at this link here: https://legiit.com/messaging/conversations
Search the username of the community member you'd like to block, click on the conversation with them, then on the right side of your screen, click on the 3 dots and then "View info"(Pictured below):
This will open up a side menu where you will see a "Block User" button as shown here:
For help or questions, please click on the purple chat icon on the lower right side of your screen, then "Customer Support" or contact help@legiit.com