My RC now is rising and hovering, but it has the so called toilet bowl effect. Doe anyone know what might be the cause and how to fix it?

are both rotors moving at the same speed, have you applied trim to stop the motion?

Hellyflyer, toilet bowl effect in coaxials is not caused due to unmatched rotor rpm, rather this happens due to vibrations in the upper rotor,

am sure Aditya's heli is having one of the following problems
1. it is missing one of the links that connect flybar to the rotor head 
2. the rotor head of top rotor is broken
3. the drive shaft of the top rotor is slightly bent causing the rotor to revolve instead or rotate on its own axis

Don't be so sure Bilal, Helis are complicated machines and anything wrong can lead to such affects.

The issue is not correctly specified here as I can't be sure that Aditiya is correctly identifying the issue as Toilet bowl issue as this is his first heli, so coming to a conclusion without understanding the issue is just a fluke

No Offense meant 

Check this:

I just googled and YouTube. On increasing throttle only, heli rises, but kind of spins like how a toy top does, like a merry go round. I'll check if any thing is broken

Ok, there was a break. The small plastic part which connects the balance bar with the inner shaft of the coaxial, had a small break (probably due to my mishandling), and the small metal pins which connected to the upper rotor were kind of loose because of the break. This caused the TBE. Anyways, removed the inner shaft by loosening the bottom screw of the respective gear, pulled it out, and used fevikwik to glue the broken part back to normal shape. I know it might not be permanent, but it works for now and the heli is a lot more responsive (not perfect, but satisfactory). Will get a new inner shaft with the balance bar from modelart someday tho, when i travel to blore probably. Thanks for all the help friends.