Please Note: The following answer holds good assuming you tried issuing print from a school machine and not one of your personal devices.
In the ITL, print jobs issued from the school machines are served by the release stations in different floors. Go to the release station adjoining the printer to which you issued the print job, and swipe your id card. Should you have sufficient print balance left on your card, you’ll be presented with an option to release your print job to the printing queue. Once this is done, please wait for a few minutes to collect the print outs (more so, if you tried printing a lengthy document).
As a general suggestion, before issuing any bulk print job, we recommend starting off with a few pages to check if printing works fine.
If none of the above solutions work for you, please contact ITL helpdesk (middle floor ITL) for support.