Hey rashid,

The major reason behind this can be network issue. Also, nowadays we know that if we don't have a plan on our phone numbers then the incoming calls and sms facilities is also stopped. So, the second reason can be that maybe your registered mobile number won't be having a plan. Now, the third reason can be sometimes these texts are blocked if you have a setting done on your phone i.e, known as DND mode. So, please check that too. If these three reasons are not valid then you have the only option to contact to the officials. Send a email to them mentioning your issue. They will resolve it.Also, no need to panic as these kind of problems are common and generally occur due to network issue.

Hope that helps.