Hello and thank you for contacting us. This is Dwayne B. and I’m an expert here and looking forward to assisting you today. If at any point any of my answers aren’t clear please don’t hesitate to ask for clarification. Also, I can only answer the questions you specifically ask and based on the facts that you give so please be sure that you ask the questions you want to ask and provide all necessary facts. Further, if you get a message asking if you want to do additional services like a telephone call that message is automatically generated by the website and is not sent from me. I, like most of the experts in the Legal categories, do not do telephone calls due to issues with State Bar rules and other concerns.
The lyrics belong to him if he wrote them the instrumental arrangements and tune belong to whoever wrote them. You would only be entitled to royalties if you establish ownership.
Anybody can "take credit" for anyone else's work although it doesn't mean they are legally entitled to do so.
Your best step now is to visit with a local lawyer and decide what you want to do. You can send the singer a cease and desist letter advising that the tunes are not to be used, you can seek some kind of arrangement with him in writing to set forth exact ownership rights and royalty arrangements, or you can pursue some other path. What you do not want to do is ignore it until something happens because the longer you wait and the more time passes the harder it is to establish your rights to the work and your entitlement to be compensated.
If your question has been answered completely then I'd offer my best wishes to you and ask that you please not forget to leave a Positive Rating (of course I’d suggest Excellent!) so I receive credit for my work.
Of course, please feel free to ask any follow up questions in this thread.