Tshirt Factory graphic license question.

[shintoburi]

Hi,
I found great tshirt design at tshirt-factory.com.
But, I need to verify commercial license usage before I purchase them.
And I need to input from anyone who is expert in this field.

their term said, I'm not allowed to:
X Use or give the artwork on sites like Teespring.com , Zazzle.com, CafePress.com, Spreadshirt.com and other sites alike;

However, I have tee shop at shopify.com which I'm going to use these design or modify the design and using tshirt fulfillment company like teelaunch or threadmeup, etc...

I'm not intend to use teespring and others, but using tshirt fulfillment company.

Is it OK?

Any suggestion is greatly appreciated.