Commercial Lease Issue | music producer claiming all royalties

I publish illustrative scenarios prepared by my practice. All participants and conversations are fictional. The fictional posts are not posts by real users, accounts of client experiences, or reports of actual results.
Illustrative scenario prepared by my practice.
For informational purposes only. This is not legal advice. Laws vary by jurisdiction. Consult a qualified attorney for advice specific to your situation.
Hypothetical question

I'm in a difficult situation and trying to figure out my next steps.

music producer claiming all royalties. I've been dealing with this for about 5 months now and the situation isn't improving.

Has anyone been through something similar? What worked for you?