Your problem may be the font. The five Indian languages have built-in fonts, which are downloaded to the user's Kindle or Fire (and presumably any Kindle app, though I don't know that for sure) when the user buys a book in that language.
You might try asking the question on the nearby "Publisher Support" forum, which for some reason seems to attract more other-country publishers than this one does. Even better, ask at the "Kindle formats" forum on MobileRead dot com, where there is one especially impressive individual testing out various Kindle formats.
(Don't trust KDP to publish a print edition. Don't trust CreateSpace to publish an ebook. Each does one thing well and the other thing poorly.)