Hello askingforhelp1,
Thanks for reaching out to Apple Support Communities. Upon review of your post, it seems that you are no longer seeing messages on your Mac from a contact that you blocked, then unblocked, on your iPhone. We can see why you’d want this taken care of, so let us help from here! Let’s start by reviewing the following article which may help: If you can’t send or receive messages on your Mac. Each of these steps could potentially resolve this issue for you.
Please let us know if you have follow up questions or if the behavior continues, so we can continue assisting. Take care!