Hello!
I am sorry but you won't be able to get admission in JNTU. You can try for CSE and ECE in adarsh college of engineering, Aditya college of engineering and technology, Aditya engineering college, ADI KAVI NANNAYA UNIVERSITY COLLEGE OF ENGINEERING, B V CHALAMAIAH ENGINEERING COLLEGE and BONAM VENKATA CHALAMAIAH INSTITUTE OF TECHNOLOGY AND SCIENCE.
Good luck!

Sorry to say that you cannot get seat in ECE or cse 

12 thousand is a decent rank don't worry there are many other colleges

Jntu Kakinada has high cutoff

Also jntu Anantapur

So don't worry

U can get other colleges

U can get a  seat in vidya Niketan college 

Also you can get other branches in jntu Anantapur eventhough cutoffs are high