Fire. Take the connection, see it as a cord and burn it to ash. If there’s an entity attached to you at the other end burn that too. You won’t hurt it much but it will piss of and bother someone else.
There are other techniques for getting rid of parasites here… (doesn’t matter if it’s someone you gave respected once, if it’s acting like a parasite, treat it like a parasite).
A much more detailed and less sledgehammer approach is to try Josephine McCarthy’s methods in her book The Exorcist’s Handbook.