Where as you are providing service of renting of warehouse.
For agricultural activity which are exempted from service tax are as:
Following services relating to agriculture are covered under section 66D (d) (Negative list of Services) of Chapter V of the Finance Act, 1994 and hence no service tax is levied on these services.
services relating to agriculture by way of—
(i) agricultural operations directly related to production of any agricultural produce including cultivation, harvesting, threshing, plant protection or testing;
(ii) supply of farm labour;
(iii) processes carried out at an agricultural farm including tending, pruning, cutting, harvesting, drying, cleaning, trimming, sun drying, fumigating, curing, sorting, grading, cooling or bulk packaging and such like operations which do not alter the essential characteristics of agricultural produce but make it only marketable for the primary market;
(iv) renting or leasing of agro machinery or vacant land with or without a structure incidental to its use;
(v) loading, unloading, packing, storage or warehousing of agricultural produce;
(vi) agricultural extension services;
(vii) services by any Agricultural Produce Marketing Committee or Board or services provided by a commission agent for sale or purchase of agricultural produce;
As your service does not include " incidental to its use" but to C&F agent service tax is liable to be charged.
Finally, let him bring permission letter to its effect from Commisioner of Exice & service tax.