Run hard and fast, and never look back...
which translates to delete the message and ignore them. Really, I find it odd that people struggle with this level of decision making.
This really is the best advice apart from reporting the user. I normally don’t ignore forum members but I cannot tolerate spam in my inbox.
PlayStation Consumer Services and Technical Support: 1-800-345-7669
PlayStation Account and Billing Support: 1-877-971-7669