If you want to continue your business as GST Registered business....You will have to file all the pending returns and have to pay late fee including interest for gst on outward supply made.
For further clarification, You may Call/ Watspp : 8779014967 Email : anandtaxconsultant2014 @ gmail.com
There is possibility to carry assessment under section 63 which proper office may pass order to pay liability if your registration is cancelled u/s 29(2), and liability are till unpaid arisen during registration period. there proper officer may impose penalty as hs deems fit.