Rcm gta

We are a GST register dealer  in  WEST BENGAL  .Recently  we have SALE some items to a( GST register dealer)  within WEST BENGAL  and  as per party Purchase order  for this  selling  purpose we have paid MINIDOOR fare (Delivery Charge)  Rs. 4500.00 to Mr. AMAR NATH  (Who is unregistered in GST)  . Please note that we have already paid fare   in cash & create a normal VOUCHER for rs. 45000.00 Now Our question is 1) RCM can be applicable 2) If Yes then what % tax is payable