How to avoid late filing Dvat Return penalty

Dear Sir,

One of my client late files the D-vat return of preceding Financila years, but the actually in the mentioned period there is no transaction of purchase and sale means it is case of Nil return.

But now department is imposed huge penalty on such late filing .

Now i am required how my client is avoid such huge penalty, though it is a case of Nil return.  

Kindly provide any case law to avoid such liability or any section on any other way to avoid such liability ?