This can happen from time to time - double up's, accidentals etc 
To get rid of those unwanted enrolment/enquiries etc files, please download the file but do not import it

The steps are as follows:

1.  Download the file, this will clear it from the download list:

 

2. Un-tick the 'Import' option on the file, then press 'OK'

 

3. Click on 'Web' > 'View downloaded files' and adjust the status of the enrolment to Cancelled and you're done!