Passport delay

[verghese_g]

My parents (aged 64 and 54) applied for a visitor visa, 3 weeks ago, at Chennai (they were approved a 1yr visit visa last year, of which they spent 6 months in the US). They were told to pay their issuance fees and their passports were retained by the official. However, their passports have not yet been released to VFS. Queries to the embassy have been met with a terse reply of "Their case is still under review" . This is causing a great deal of anxiety and they've already had to postpone their flight twice.

Could someone explain what's going on? Is there any way I can expedite matters? Do I have any legal recourse if their passports are held indefinitely?

I'll be grateful for any help on this matter.

Thanks

Verghese