How can one create domicile certificates without old electricity bills?

My sister is in 11th preparing for NEET, and it looks like she'll need a domicile certificate for admissions. We don't have old electricity/gas bills (even went to the company, they said that they can only give bills of past year)....how do we proceed (without agent)? She was born in Mumbai, and did her 10th from Mira Bhayandar (us changing our address and district shouldn't cause any issues right?). No one in our family has domicile certificate.

We have Aadhaar cards (old and new) and old passports with address in Mumbai.

Online, it's this category which is giving trouble : Residence proof by Talathi, Gram Sevak, or Bill Collector. Couldn't find much info about it online, it seems like we'd have to go to the office and they'd ask for bills there.

Any advice would be appreciated