I have no idea what karnatic classical music is, however before one learns anything one has to go through the basics, it is a test really, if you pass it you carry on. I am totally self taught (not necessarily in the recognised correct way) however I have found over many years that I have lost and refound the interest which in turn has brought me the progress which now allows me to play quite confidently both by ear and less confidently by reading music, I persevere nonetheless. I have tried many instruments from cheap keyboards to brand new £3000 Technics organs, I have finally found my home in the Tyros 4 by Yamaha which I can produce magic on with lots more learning to keep me happy for the rest of my life. Persevere my friend, you will be rewarded if it is to be....Practice is the key, but not necessarily the type of learning laid out in books....Find your own way, but keep going.
Hope that helps
Pete