Casio — gst wrongly deducted

Address:

Kamrup Metropolitan, Assam

During my purchase on 15 July 2017, from CASIO store (RD Retail Venture), GNB road Guwahati. GSTIN - 18AAIFR4062M1ZR, email- [protected]@gmail.com, invoice number - RDRER/1171.
I brought a watch worth rs 5845, where i found that GST might have been wrongly deducted, amountig to Rs 639.36 for both SGST AND CSGT.
Please look into the matter and get back to me.