Need help!! Received a DMCA email yesterday.

I have a website that I am reselling products. Yesterday, I got an email from someone and they told me that they represent a company regarding copyright infringement and to remove ALL products related to the company from my website. If not, they will report my service and report my PayPal account (it's a business account).

Here are my questions
1. Where do I go from here?
2. How do people run sites like mine without having any issues with PayPal?
3. How do I keep my PayPal safe?
4. Do PayPal stealth accounts help?
5. Is it possible to create a business PayPal stealth account?

Thanks