LittleApp — Voucher code bought for Domino's not valid

Address:	Panchkula, Haryana, 134116
Website:	littleapp.in

I bought a voucher worth 500 for 331 on 31 may..it is 13 digit..when I try at Domino's.. site expects 16 digit code and hence gets error pop up card no.not valid...and the voucher is expiring on 15 July...when I called customer care..they put me in queue and the call ends after sometime..I want my money back.litle app should not offer such deals or shud be responsible for end to end delivery..