We purchased a property Which had two 2 CTS no's but both party thought it had only one CTS no but after 20 years we came to know it has 2 CTS and the seller party are not ready to give the property how file a dispute?

Hello! Need some advice on property related problem for my friend I'm copy/pasting the query he sent to me.

My dad purchased a property(which we are living in currently) on 1999 year for Rs 5 lakh from his cousin and my dad was careless as he is purchasing from his cousin,So the total property actually had two CTS no's in them but my dad and his cousin also didn't know about that they thought total property has only one cts.no.

After many years on 2011 my dad got to know about that it had two CTS no's and only one cts.no was on our name, so they thought his cousin will sign the papers of the other cts.no as it was a mistake but he and his wife denied saying they will not give it and demanded 4-5 lakhs but my dad didn't had that much money and tried all other ways to convince but they didn't agree and after that, in 2012 my dad died due to health problem.

And till now we're requesting them so much we even agreed to pay 2-3 lac but these people are not agreeing Now they are forcing us to free the space and leave the property and demanding 9-10 lacs which is 70-80% higher than the actual market price. Sorry, I'm mentioning all the size and details mentioned in the documents below by point because I don't want to confuse you guys in-between:

1. The total size of the property was 60x50. But the cts.no which we purchased is 45x50 sqft and the other cts.no size is 15x50 sqft.and the size stated in our document is 220 sqmtr which is somewhat equal to 45x50.

2. The boundaries defined in the documents is including both the properties like " The North, South & East directions has road and West has a home of our relative all the land in between is sold to them(us)"so the property which is not in our name comes under the boundaries defined. (so people saying this can help us if we take legal actions)

3. The construction & open space in the land is also defined including both properties, as the other property which is not in our name has 300 sqft of metal sheet roof and remaining open space which is also defined in the documents.

4. The property is in our under from last 20-21 years, we're staying here only, so does this help if we fight legally?
I have read that there's been an act came in 2019, (Article 65, limitation act,1963 adverse possession) which tells that if you're living in property more than 12 years and the real owner didn't take any measure to get it back within 12 years than we can file a case to get the property on our name as adverse possession.

I know the size mentioned in the document is the main thing if we had the total size of both property mentioned in the document then we would have easily won that, but unfortunately, we don't have. Now I want to know what steps we should take further, as the point 2,3,4 is in our favour, so these can help us if we go to court? or else what we should do?

Please help us if you know about this or solved these kinds of cases, Thanks in advance!