I was registered in service tax, then got registered in GSTN in June-2017. However, as per GST rules, GSTN registration is non-mandatory if annual turnover is below 20 Lakh. My turnover is 10 Lakh and registered in same State (both service receiver and providers are in same State). Please, guide me setp-by-step procedure for cancelling the GSTN registration. Also, let me know cancellation will be an online process or through fill a specific form?