TDS doesn't deducted from old and new company.

I have switched company in december and my previous company didn't deduct any tax for my december salary. I have chosen old tax regime in my previous company. After switching to new company I have selected new tax regime and by mistake I didn't submitted form12BB as I didn't had much knowledge. Now from past 2 months my new company didn't collected any tax, and now I'm concerned because almost 4 months of salary tax didn't deducted. I checked that if I pay this tax while filing ITR they will charge me interest of late tax. And tax selection date is closed in new company so I can't submit form12B. So is there any way that I can pay tax manually so I'll save late payment fee ?