Cancelling the Email account will delete all the mailboxes you have connected to this Email account. The account will be cancelled in the next renewal date. After cancelling, there will be no option to enter the mailboxes or restore the mailboxes data you have in the Email account. Cancelling the Google Apps for Work account will delete all the mailboxes you have connected to this account. The account will be cancelled in the next renewal date. After cancelling, there will be no option to enter the mailboxes or restore the mailboxes data you have in the Email account.
Cancelling the mailbox will not cancel any other subscription (premium package, domain, etc.)