Gst on transportation of goods

If  a transporter registered  carries the goods of registered person and charges freight for carrying the goods and GST is payable by the person who pays fright to transporter in reverse charge @ 5 %
Now if that transporter (A) takes trucks from other transporter (B) registered or unregistered and pay fright to them but transporter B from whom we take truck does not issue consignment note whether we have to pay GST on freight in RCM if yes at what rate 5 %?.
Second  if that transporter (A) takes trucks from other truck owner (C) registered or unregistered under GST and pay fright to them  but truck owner C from whom we take truck  does not issue any bill  whether we have to pay GST on freight in RCM if yes at what rate 5 % or 18 % ?.
If transporter A pay GST on RCM to transporter B or Truck Owner C and there is no output  payable by transporter A  whether A can take refund of GST Paid in RCM
If Registered person who deals in any business takes truck from truck owner registered or unregistered under GST and pay fright to them  but truck owner  from whom we take truck  does not issue any bill  whether we have to pay GST on freight in RCM if yes at what rate 5 % or 18 % ?.