Use the service that originally billed you, even if you now use Chatbot on another device.
App Store
Open iPhone Settings and tap your name.
Select Subscriptions, then Chatbot.
Choose Cancel Subscription and complete the prompts.
If Apple shows an expiry message and no cancel button, check whether cancellation is already recorded. Apple cancellation help
Google Play
Open Google Play with the purchasing Google Account.
Tap your profile, then Payments & subscriptions → Subscriptions.
Select Chatbot and choose Cancel subscription.
Complete the confirmation.
Website
Sign in at Chatbot on the web and open Account Settings → Plans → Cancel Plan. Follow the confirmation steps.
Check the end date shown after cancellation. Cancelling a renewal is separate from requesting a refund.