If a company purchased software on 31.12.2019 worth Rs. 10 Lacs incl GST but company fails to pay the amount within 180 days do the company needs to reverse the same with interest @ 18% even if company does not utilized the input but company shown the same in GSTR3B under all other ITC. Is it necessary to take all the input or reversal before September 20 return for 19-20. What if my payment is pending on 30.09.2020 for that bill. Does the input get laps proportionate to the o/s amount after September 20 return if I don't take in the September 20 month or company have to pay the amount before September 20 return.