Spoilt Nandini Gulab Jamun Mix

I brought a pack of nandini ready to eat gulab jamuns on 22-july-12 from the nandini outlet in rpc layout. The date of manufacture was was june-2012. But since it was mentioned 6 months for expiry I bought the item. When I opened it the gulab jamuns were spoilt and the syrup was foamy. So I returned it immediately, and asked for refund or replacement of the product. But the shop keeper was completely indifferent of what I had to say and was sending me off. Please help me as to what has to be done.