Vat returns for unregistered period by builders

One of my client is engaged in Construction of residential houses. They have started our business in 2010 and We have obtained Registration under MVAT Act in September 2013 as per Circulars issued regarding vat liability imposition on builders.

However till date we have not file any VAT Return. Now my query is whether i should e-file vat return only from the period of Registration i.e.September 2013 onwards or i have to file returns even for UNREGISTERED period i.e. from March 2010 ? and so we have to all vat liability along with interest ?
Kindly Clarify me on the same.

Thanks & regards