You can find account and calendar management in the upper right corner under the Account menu:
Navigate to Account > Calendars
Click Delete from within the "Delete everything" section at the bottom.
Note: Deleting your account is irreversible and cannot be undone.
Reclaim will clear all Reclaim-created events—including any synced copies of events from Calendar Sync—as well as delete all your user and account data from our systems. This process can take several minutes to complete fully.
If you have a paid seat as part of a larger team, your seat will become available for your administrator to assign to someone else. If you are the sole user and have a paid plan, your subscription will automatically be set to not renew at the next billing cycle.
Some advice: consider disabling your Habits and Calendar Sync policies first, before you delete your account. This will give Reclaim time to remove the events on your calendar before you revoke it's access to your calendars.
If you don't do this, sometimes deletion can fail to remove 100% of the events, especially if you recently signed up or did some other action that caused a large amount of changes on your calendar. This is because Google can "rate limit" Reclaim's work.
If this happens, wait an hour and then sign back up temporarily and connecting the impacted calendar, clicking No to all other questions. Then re-delete your account.