You can delete your account. To do so, contact us at firstname.lastname@example.org or via our Support chat and we will take care of it.
Doing this will erase all the data associated with your account. This includes any lists you've created and all the statuses you've entered.
If you don't want to lose all this data, you can cancel your plan instead. This way, you'll still have your Heepsy account in case you want to subscribe again in the future.