How to delete custom metadata field in Mandrill when the field is indexing?

I've added custom metadata fields in http://ift.tt/2yAAIlY. All added fields after adding had status 'Indexing' and later - status 'Active'. But one field has status 'Indexing' for a very long time. And I want to delete this field with status'Indexing', but there is no option 'Delete' near button 'Edit'. How to delete the custom data field. Help me, please! Thanks.