Yes. Upon your request, both your database and your credentials will be permanently deleted.
Before you submit a deletion request, it's your responsibility to export or back up any data you want to keep. Once deletion is initiated, that data cannot be recovered through your account.
Please note that backup copies of your data will be retained for the duration of the standard backup retention period. However, Unusual Software GmbH will not be able to associate those backup copies with your terminated account.