RCM ON ADVOCATE

if you are receiving any service on which RCM is applicable then as per section 24 of cgst act, it will be mandatory to have the registration.
also 20 lakh limit is not applicable on RCM supplies.
however, as per serial no 45 of Notification number 12/2017 provide exemption of arbitral supply to business entity if its turnover in the last financial year is upto 20 lakh.
so, in my opinion you don't have to pay gst on such services.

The DUE DATE for furnishing of Annual Return in the FORM GSTR-9 / FORM GSTR-9A and Reconciliation Statement and Audit Report in FORM GSTR-9C for the financial year 2017-18 has been extended from 31st August, 2019 to 30th NOVEMBER, 2019.

REMOVAL OF DIFFICULTY ORDER No. 07/2019-CT dated 26.08.2019, issued by the CBIC Department.

Hence, the latest Due Date to file ANNUAL RETURN ( GSTR-9 and GSTR-9A ) and Reconciliation Statement and Audit Report ( GSTR-9C ) is 30.11.2019.