The default is:
Email,Name,Phone,Notes
jdoe@domain.tld,Jane Doe,1012023434X1111,test
You've got some extra fields there that I presume that you added at Admin panel -> Manage -> Forms -> Contact Information. I would try running the default is see if you have issues with that. If you do not, then the problem is likely with the format.
Also note that if you do not have a variable set for a field it says Only fields with variable defined can be imported. You should go to Admin panel -> Manage -> Forms -> Contact Details and make sure that you populated the Variable field for the ones that you are trying to import.
Lastly you can create a new csv file put a single user in and slowly add fields to their entry in the file and try importing to figure out which field it is bombing on.