Do you have a link? I'll start looking, will edit this comment if I find it.
Edit: Link to Steam total spend: https://help.steampowered.com/en/accountdata/AccountSpend
Edit: This seems to be how to do it for Amazon: https://www.amazon.com/hz/privacy-central/data-requests/preview.html - My data hasn't come through yet so I don't know how difficult it is to get the sum of all orders/refunds.
Do you have a link? I'll start looking, will edit this comment if I find it.
Edit: Link to Steam total spend: https://help.steampowered.com/en/accountdata/AccountSpend
Edit: This seems to be how to do it for Amazon: https://www.amazon.com/hz/privacy-central/data-requests/preview.html - My data hasn't come through yet so I don't know how difficult it is to get the sum of all orders/refunds.