Demand as per 143(1)

Hello

Received a demand of Rs. 1.5 lacs alongwith interest u/s 143 (1) in intimation for AY 19-20

Earlier I filed ITR-4 (which was a mistake) and reported exemption u/s 10(26) - scheduled tribe exemption. However, I also showed business income and tax was calculated but I left it unattended and submitted the return. However, I should have not shown any income and just reported exemption . I confused exemption for deduction.

can anyone help with the way out ? Shall I file rectification ? If yes, then shall i submit XML or just reprocess? Or there is other way out ? 

PS - Scheduled tribe exemption is applicable to the client.