Hi Rinaz,
Execute the report SXMSALERT_LOGREADER as Indrajit suggested.
Check the Alert inbox (RWB --> Alert inbox) for any alerts received.
Check the below blogs for trouble shooting.
http://scn.sap.com/community/pi-and-soa-middleware/blog/2005/09/09/xi-alerts--troubleshooting-guide
http://scn.sap.com/community/pi-and-soa-middleware/blog/2005/09/09/xi-alerts--step-by-step
Regards,
Pranav