The deferred filing of Goods and Services Tax returns won’t provide much of a breather for mobile phone manufacturers, which face a 6 percentage point rate increase on handsets from April 1 and a further drag on demand, already plunging amid the Covid-19 outbreak.“Though returns can be filed till June 30, any phone sold after April 1 (including inventory) will be billed at 18% GST (from 12% currently).