Requesting deletion of data on ColorNote

I have been using the app for years before I started caring about privacy concerns. Now I backed up all my notes to my hard drive and wish to wipe them from the app, so I want to know: Should I erase them manually, then delete my account? Just delete the account directly ? Erase the notes and request an account deletion from the devs themselves? How can I make sure there aren't backed-up versions remaining on their servers?* **Their privacy policy says: "Please note, however, that there might be latency in deleting information from our servers and backed-up versions might exist after deletion."**