Magicpin — coupen code was wrong

Address:

2/41 kotla village mayur vihar phase 1, New Delhi, Delhi, 110091

I have completed target of 650 cash back points and they have given me voucher of book my show worth 350 and whenever i want to use it error has came of invalid coupen code magic pin is not trust worthy app many times this app disturbs me btw the app is good or we can say app is best way to get cash back but sometimes it create problems first time i have complaint about anyone in my life and that is magic pin