Service tax on gta as per reverse charge

Yes, since GTA service is covered under Full Reverse Charge. The Service Tax is payable by the person liable to pay Service Tax (belonging to specified category-Body Corporate, Factory, Society, Partnership Firm) and located in Taxable territory.

ST should not have been charged by agent. You should ask for a credit note for the same. 

Gta is appicable only to people who ussye consignement nite since it appears agent is not issuing consignement note to you hence reverse charge is not applicab he can charge service tax if ihe is registered undrr cargo handling and provid8ng service like loading unloading packing along with transportation