Try to get earlier appointment ( If someone cancels ), other wise after 15 days, inform CIC the date of appointment and reason in comments. It will be extended but you will not be notified. Nothing to worry about.
"As a sponsor I do not have a voter id and my fifth and middle class marksheets or certificate. I just have matric certificate.I have adhaar card only."
Are you a CC ( Since ) or PR, in which Year you passed Matric?
Nothing to worry, just book earliest possible date and send ref # to CIC, Already aware of the situation and try reschedule on earlier dates if possible.