had faced a long time ago on another card. so basically in T&C you will find somewhere that it is like 'offer valid till stocks last'... the are limited seats for an offer..try using another indusind code. on the legend card, you should get 2 codes - one code is for the bank card variant, and another is for the network (visa signature). see if it helps.
also when i checked, the offer validity was starting from 30th July. since you made the post on Friday, it might have given you this error.