There isn't any explicit "rollback" feature available through the excel connector.
Is there any way for you to uniquely identify the data that you imported? If there is, and you can isolate it through a query, then you can bring the data into the excel connector, hightlight all of the data, and then use the "delete objects" command to delete all of the data.
Is there any way for you to uniquely identify the data that you imported? If there is, and you can isolate it through a query, then you can bring the data into the excel connector, hightlight all of the data, and then use the "delete objects" command to delete all of the data.