Penta Meneka - Straight up scam

I went there to get a phone repaired. The usual process of repairing is to do the checks and tell the customer what is the problem, give an estimate and if I agree, do the repairs.

Those fuckers have cracked this process of mine. During checking, the man twisted the battery beyond reuse and told me the battery is broken you will need to replace it.

I was left with no option but to agree. The man replaced the battery took 900 bucks and told me you have a six month guarantee.

Within 5 days the phone started having a new issue of battery suddenly draining and conking off. I go again to the shop and the owner goes somewhere inside Penta mall and asks me to wait at his shop, comes back after 45 mins an hour and says the phone is fixed now. He has replaced the battery. With the benefit of hindsight, I now realise this was a lie.

After 5 days, the same issue comes up and I again have to go back to the same shop. The man changes his tunes now. He now claims- battery is ok, it's not a battery problem, shows me some Ampere ratings and tells me it is a board fault and it will cost me 2500 bucks. I refuse, he says okay I will replace the battery , this time it does not take 45 mins but 15 mins but when the phone is switched on it is only charged 5%. I ask him explicitly did he just turbo charge and put the same battery back. He laughs and says no. He says -he has replaced the battery. Turns out, he has not. It is the same battery again.

He also takes the pic of the phone front and back before returning it to me. I think all the shops are connected. I guess he may have shared my phone pic on his penta meneka WA group and if I go to some other shop they would know in advance about this issue. I again ask for money back, since he did not fix the issue, he straight up refuses.

What are my options here. I checked with a local - he said you need to scream at these guys to get the money back.

EDIT: Folks asking for the name of the store, it's a no name store outside Penta Menaka. No Online listing, no google maps listing. Nada. They have cracked this model also so that people don't talk about them online. They are literally more than 100 stores there but only 3-4 have an actual online listing. IMHO it's an elaborate scam where the scamsters have thought these thing through.