RCM applicability for NGO

Friends i have a doubt.....An NGO which is registered under Sec 12 AA of Income Tax Act has received security services from a non body corporate....The NGO is not registered under GST....But as per Notification no.29/2018 of GST, GST has to be paid on RCM basis for security services if the service provider is a non body corporate....Now how can the NGO pay GST?...Is the NGO required to be registered under GST only for this purpose?....Kindly suggest friends