Instant messages from blocked address

 A particular email address used to belong to a friend, but hasn't in a long time. I believe it has been hacked or taken over by a spammer. I have blocked this address and yet I have begun receiving an instant message from it every time I first log in to messenger for the day. I blocked this email address quite a long time ago. I began receiving the unsolicited instant messages about two weeks or so ago. The messages were initially in English and were attempting to be flirtatious. Now the messages are in Spanish, and I assume have the same sexually suggestive message. As I say, I blocked this address a long time ago. How can I stop getting messages??