Igst value for pi967 lithium-ion batteries

Also, I purchased a Mobile from Singapore whereas the Seller has mentioned it as "PI967 Lithium-Ion Batteries" and on enquiring, he says that the category is correct so will it create any legal problem for me? Should I force him to update it correctly? Seller and DHL have done all the custom related documentation on my behalf and they have charged me Rs650 for the same.

As the entire rates are fed into the system as inputs, the revised rates may not have been modified in the system of the seller.  May be a minor understanding.  Bring this to the attention of the seller and demand for refund, enclose the auhentic slab if available, and copy of noting such slab for that goods as per his calculation.  (basing on which seller is recovering GST).  Make a complaint to GST authorities with authentic invoices and seek information as to whether the recovered amount is being remitted to Govt or not..

Thank you, Sir, for your reply.

The Seller is from Singapore so he simply said that we don't take any responsibility for customs in India, though he did make the mistake of showing it as Lithium Battery. And the DHL team has incorrectly entered it in another category instead of Lithium Battery which resulted in me a loss of Rs1000. I was forced to make the payment as the shipment was on Hold but I would complain regarding this to government authorities after receiving the product. As I had questioned them and many might have not. And, I also suspect that the extra Rs1000 is being kept by DHL. 

The GST Council has decided to reduce the GST rate on lithium-ion batteries from 28% to 18%. The new rates will come into effect from July 27, 2018.

The revised rate of 18% is only applicable to lithium-ion batteries that are sold separately. The lithium-ion batteries fitted in electric vehicles (EV) attract 12% GST.

Thank you Sir for your reply.