Reverse service tax

I would like to know if in GTA,Service tax was paid to the GTA and the same is deposited by GTA to the Govt, whereas under RCM the liability to pay service tax was on the assessee and thereafter the department issue a notice to the assessee for such demand of service tax as the onus to discharge liability was on him. Do he has to pay the service tax again to the department or any remedies available in law as the same is paid by him to the GTA, which is deposited to Govt by GTA. Can dept. take twice the service tax amount on same service from both assessee and GTA? Please suggest with reference to case laws and evidences required to proof that the same is deposited by GTA