Hello Aspirant ,

If you haven't got a reply even after 15 days you should contact them back through calling or by sending them emails and they will reply you back. You should also check your calls log or emails(check spam folder) thoroughly.

Most of the companies reply back in due times and this might be a mistake from their side , it is also possible that you might be rejected for the position of service desk role but companies are supposed to tell you this so do not panic they will reply you .

Hope this helps.