worst customer support

first of all sorry for my bad english. i ordered a mobile flip cover on shopping.rediff.com on 16-07-2014 whose order number is 10053365 and which is delivered to me on 22-07-14 but the product i got was totally different from what i had ordered so i call there customer care number and also written an email to them for refund or replacement but they said to me that i can keep the product as compensation and they will give a gift voucher of worth rs 200 as a penalty for their mistake but till now they have neither replaced the product nor given any gift voucher which they were gonna send me through email… i have emailed them and calling them to ask about it but they mostly dont pick the call and if pick it ever they usually take 8-10 minutes to do so and then they say that they will send the G.V in next 24 to 48 hours but almost 8 days have gone and no action has been taken by them…