if in third allotment you are alloted a seat in any branch you first have to pay the fees otherwise you will not be considered for further upgradation under any case and then you will not be considered for spot rounds also.
i would advice to pay the fees and wait till the admission process is completely over, if even then you are not alloted your desired branch then you can cancel your admmission and your fees will be refunded to you after cutting 1000 rupees as service charge.