Looking for a salesman commission system plug in

Hey all!

I am looking for a plug in where I, and the sales people, can track their sales progress and commissions. We do not use Woocommerce or any other e-commerce system on our website. We are selling a service with a monthly fee attached to it and we need to track each sales person’s sales and commissions. They work on a tiered commission based.

Loking forward to your help. ??