Datawind — PRODUCT NOT DELIVERED WHICH WAS SENT FOR SERVICING

i had purchased a product from datawind innovation pvt ltd had some problem in it so i have sent it to Amritsar for servicing and replacing the product they asked me for demand draft Rs.1,500 . i made it and sent along with the product through coriour blue dart my detail are below : name : mohammed spiritwala address : 18, jawahar marg below bohra masjid indore (M.P) product : ubislate 7c+ demand draft detail : bank : state bank of india number dd : 663390 they told me u will be getting back after 15 days but 3 months passed when ever i call they tell sir wait 1 week more but they are not sending it back. i hope u will resolve my problem