How to import dumped Mongodb?

You may have to specify the authentication database

mongoimport -h localhost:27017 --authenticationDatabase admin -u user -p -d database -c collection --type csv --headerline --file awesomedata.csv 

When you do a mongodump it will dump in a binary format. You need to use mongorestore to "import" this data.

Mongoimport is for importing data that was exported using mongoexport

The counterpart to mongodump is mongorestore (and the counterpart to mongoimport is mongoexport) -- the major difference is in the format of the files created and understood by the tools (dump and restore read and write BSON files; export and import deal with text file formats: JSON, CSV, TSV.

If you've already run mongodump, you should have a directory named dump, with a subdirectory for each database that was dumped, and a file in those directories for each collection. You can then restore this with a command like:

mongorestore -h host.com:port -d dbname_test -u username -p password dump/dbname/

Assuming that you want to put the contents of the database dbname into a new database called dbname_test.