Stamps.com might as well be called SPAMS.com
Good luck trying to cancel the account. Their website directs you to follow the steps noted below in order to cancel, but the close this account option is SIMPLY not there!
"In Stamps.com Online: Open the My Account drop down menu and select Manage Account. In Stamps.com Windows PC Software: Select the Account Tab.
Select the Change/Cancel Plan Tab.
Click close this account.