Tortious interference is interference that leads to harm caused by a party outside of an established business relationship. In other words: someone got in the middle.
An Example
I have an agreement to represent you.
My agreement has terms that allow me to be your exclusive sales force.
You will pay me 10% of your earnings for my service.
I book you on a cruise line.
You don't like my representation, and you ask the cruise line to book you directly.
The cruise line books you direct.
The cruise line got in the middle.
Musician after musician would contact me and ask me to get involved with their agent disputes. I couldn't. I felt terrible because I want to be helpful. But,
I didn't enter an agreement with the agent.
The musician did.
Musicians, this is on you.
You have a responsibility to know the terms of your contracts. When looking to enter a relationship with a service provider, ask for their terms upfront. Examine their contract with a licensed legal professional. Negotiate the terms you need to feel comfortable and successful, but also so that your agent has the freedom to do what they do best - sell.
Don't ask another party to get involved.
It's not their responsibility to solve your disputes.
The responsibility is yours.
Don't ask others to get in the middle.
Others: Don't get in the middle.