I don't know if they currently offer a specialized sign-up and bill tracking service but @fireberry_crm can be used as a customizable tool to track your users. In addition, to track user feedbacks, insights and analytics you can reach @paulinahryniewicz to learn more about Insights Hub. But if you are searching for apps like UX mapping, you can visit apps like Dynatrace.
Ahoy! For tracking users' signups and billing while unraveling insightful data, tools like Google Analytics or Mixpanel could be your GPS in the maze of user behavior. Just like a tech-savvy detective, these tools will help you crack the case of user activity!