If I am receiving a 1099 K from my merchant service provider do I also need to fill out a W9 for a company I do work for? Don't want to pay taxes twice or do extra paper.

Hello,

I have a question regarding 1099 K and a W2. I do digital marketing and use PayPal as my merchant service, because of that I receive a 1099 K each year for the work I have performed. I recently received a request to fill out a W9 from a company I did work for. I do not wish to fill out a W9 with them because they will in turn file a 1099 and I will be paying taxes twice on that income. 

I am correct in denying their request for a W9?

Thank you.