I don't think there's any loophole for airtel or ace. There's huge number of people who are ready to have it paid but aren't able to get it. Also cashback vs fees is highly justified, you can recover the fees within couple of months, what else you want ? Heck It could've justified with 1000 also.
It's always supply vs demand in business, in both these cards demand outweighs supply a lot so they won't budge. Close it if it's not relevant for you.