You will be eligible to sit in csab even if you do not pay partial admission fee in josaa but if you are allotted a seat in josaa then in order to confirm your seat you will have to pay the partial admission fee if you do not do so you will be disqualifies from the counselling and if you pay the fee in josaa and get your seat confirmed then also you can sit in csab if you are allotted a new seat then its fine otherwise it remains as the seat you were allotted in josaa and if you withdraw from counselling after round 1 the you will get refund as per bank details you have provided.