in order to delete your Todoist account, please go to the Todoist Preferences (the gear icon in the top-right corner) -> Account and use the "Delete my account" link at the bottom, but please note - this will completely and permanently remove your account with no further option of recovering it.
Also, to make sure your Todoist Premium subscription is canceled, use this link: https://email@example.com to see a list of your payments for Todoist. If a payment confirmation links to an active payment subscription, cancel it directly through PayPal.
I am sad that I must cancel. I only have the Free Account, as that is all I can afford. I was happy when I first found Todoist for my computer...it works great there---except on my mobile, only one project would open there...clicking the others created an error message, stating, "Sorry, but Todoist has stopped working."
I was offered the option to report it, but that proved problematic from my mobile, as well.
Shortly after finding Todoist, I discovered "Catch Notes". I have used that app (the free version again!) extensively on my mobile, and prefer that service...along with some associated notepad apps which when used, download immediately & automatically, to Catch.
Again...sad that your service worked only on my PC...I am so sorry to be "dumping" it. (-_-)
The Original Earthmom