If your contract was cancelled and you didn't request the cancellation yourself, there are mostly two reasons.
Another provider cancelled your contract on your behalf. This happens if you sign up with a different provider and ask them to cancel any current contract.
We cancelled your contract automatically due to missing payments. Please check your e-mail regarding payment reminders or dunning information and your app's payment history. If there is no reaction to the reminders and the dunning process, your contract gets cancelled automatically.
In both cases, feel free to reach out to us to get more clarification on the situation.