Two emails received by customers after purchase

I have a multisite (influencer.biz) and people pay to run their own blog/ecommerce store. I want to make sure it is its own store with no connection to my multisite.

When someone bought a product from one of the blogs (howtobooklets.net) it sent out a confirmation email saying thank you for your order here are your details (great) but my main multisite also sent out an email saying thank you for your order here are your details.

How do I stop the main email from going out so they only receive one from the actual blog/store?