If you try to resume a suspended account from your Reseller Account and get:

Error: You have no permissions on this plan

Check that the Plan for the end user account in question has full permissions set.

Go to Plans tab:

If next to the lock icon for the Plan in question is the text: FULL - it means no issue.

If FULL text is missing then there is a permissions restriction in place.

To grant full permissions:

click on the lock > unselect all checkboxes > commit changes

Full plan access should now be restored and you can resume suspended accounts, etc.