If your membership ended when you expected it to last forever, here's what most likely happened and how to pick it back up.
Lifetime discount, not lifetime access
The most common mix-up is the Lifetime Discount. That's a discounted price that stays the same for as long as you keep your membership, not a one-time purchase for permanent access. Your membership is still a monthly or annual subscription, so it renews or ends on that schedule.
Check your subscription status
Your membership is managed by your store, so that's the best place to see what's going on. If Bend shows as expired or canceled, your subscription reached the end of its term or auto-renew was turned off.
On iPhone
Open the App Store, tap your profile picture, tap Subscriptions, then select Bend.
On Android
Open the Play Store, tap your profile picture, tap Payments & subscriptions, then Subscriptions.
How to start again
To pick your membership back up, open Bend and subscribe again from the payment screen. If you think you still have an active subscription, tap Restore Purchases on the payment screen, then close and reopen the app.