Cancellations take full effect on the first day of the next calendar month, at which point your account will still be usable, but will be automatically downgraded to the Free package level.
Because it takes some time for the cancellation to take effect, Twilio SendGrid recommends you secure your account if you have not already:
Run a virus and malware scan on all computers and servers that access Sendgrid.com
Review recent IP's that logged into your account via the IP Access Management page in Account Settings.
Ensure any installed content management systems such as Apache, PHP, Perl, etc. are up to date.
Verify that your account credentials and API keys are not publicly listed on code repositories or associated comments on sites such as GitHub or BitBucket.
If you run into issues Cancelling your account, please contact our support team.