The points that I redeemed disappear from my accountUpdated a year ago

Since you converted your points into rewards, it created a coupon. This coupon has no expiration date, so you can use it on a future order.

To view your rewards, you have to log in to your account, and click on Leaves points:

Then a widget will appear and you can scroll down to see your rewards:

By clicking on Your Rewards, you'll see the coupon codes you have created:

If you click on view, you'll see the code to apply on your order.

You can then copy and paste this code at the checkout: