Rent commercial

sir mera rent income hai from last 5 years tab main gst me tha 3 saal tak TO more than 2000000.00 magar muje bataya gaya ki limit 40lakh tak hai tho main cancel kiya 2 saal tak ab main August me fir se registered gst liya aur gst me invoice raise kar raha hu, kya muje piche ke 2 saal ka gst pay karna padega kya