It is not clear as to whether the school is a Public Authority or not and what exact remedy you wish to have at this point of time.
1.Submitting resignation is a legal formality, irrespective of the past procedure followed by School.
2.You can file RTI Application to school and can obtain such records that confirm your presence and working in the school on that day. Remember that every task is computerised now, and if you fail to follow the procedure like signing attendance register or bio metric attendance, the system can not go and identify your teaching in the class. For those instances, it is your duty to offer explanation for not following the accepted/laid down procedure and then demand salary for your working through a detailed letter supported by evidence to the concerned authority.
3.When School Management has not said any thing, do not presume those things yourself, no school can in writing state that Casual Leave is not paid leave. First let them dare to say on record.
4.All RTI Applications have to be sent by Regd., Ack due or Speed post, and the delivery can be tracked in indiapost website, and one can download delivery status and can save the screen print. There is a laid down procedure in RTI where you have to file first appeal if PIO fails to respond within 30 days from receipt of such application, and once again a self attested application has to be enclosed to your first appeal before Appellate Authority. So your doubts are not founded by any reason.
5.Simply because RTI Application was not responded, they will not impose any penalty against PIO, as deliberate and malafide denail even after first appeal has to be pointed in the second appeal. Even after all this, it is not mandatory to penalise PIO and it is discretion of Commission and appellant can only pray and can not mandate.