sectiy 148

Then AO would do the Assessment u/s 147 as per the available records with him, also the information find by him. And make your demand order. If you not pay that too then AO will make you Assessee in Default and charge the interest Penalty u/s 220 & 221.
Also, for the tax on income assessed u/s 147 AO may levied Penalty for Under Reporting/Misreporting.

Suggestion- Please reply within the time and don't make AO angry. If you could not do it self then find any CA and take care of the case at early stages.