Exam form hard copy submitted late

You mean you sent it today?

Call the examination department tell your genuine hardship for delay. If the Examination Board is convinced with your explanation, they will permit you to appear in the ensuing examination. Thus trying connecting with the Exam Department and appraise your situation rather than feeling tensed.

Dont get Panic or worried, Just Relax & study, your Exam form will stand accepted as you have filled it online, nothing adverse will happen, you will get your Admit card for the exams. No need to call the  exam department. This type of things & mistakes / Delays are happening with many students & ICAI does not bother for that & delays of 8 - 10 days. Keep the Despatch Reciept Proof with you carefully. Yes had it been the despatch beyond 20th March then there would have been a need for you to make a request to ICAI, but in your case it is not required. 

Now its your choice what to do, Go as per some other panelist advice or take my opinion

Dont worrie once you fill exam form online you will get your hall ticket by online only.

Whereas you will not get your hall ticket by post as well as you need to carry a photo identity proof during exam because you not submit form.   

Can you please tell finally you were allowed or not to appear in that exam ....??