If I accidentally deleted an assignment when i was importing new assignment groups. Is there Any way to retrieve that assignment?
Canvas has an "undelete" function which may help. Have a look at the document and video atUndelete
Brian, Michael has given you a great tip; /undelete works in most cases. But sometimes it does not, and at that point, you should submit a ticket to Canvas Support who have been known to work miracles on many an occasion (How do I get help with Canvas as an instructor?).
Retrieving data ...