Looking for a way to track remaining personal training sessions

I currently have a setup using Webflow, memberstack.io, and Stripe. Everything right now including our invoicing and session tracking is done manually.
We have users purchase personal training sessions in a package of 5 sessions.

As a client, I want a way to purchase private training sessions and also see how many sessions I have left. Some clients buy more than one package at a time, so they can have more than 5 sessions at a given time.

The trainer currently keeps track of how many sessions their clients have on a Google Spreadsheet.

Is there a solution that allows for this type of functionality, where the user can:

  1. Log in to our site via memberstack.io
  2. Pay via Stripe
  3. See their # of remaining sessions increment on their profile page?