Am I the only one dealing with ghostwriter wants credit??

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Illustrative scenario prepared by my practice.
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Hypothetical question

I've been trying to resolve this on my own but I'm stuck.

ghostwriter wants credit. I've been dealing with this for about 16 months now and the situation isn't improving.

The contract was signed 22 months ago. I have a copy of the original agreement. The total amount in dispute is approximately $143,000.

Should I hire a lawyer for this or try to handle it myself?