Bought a phone from online store turns out it was stolen!!

Hi, I'm from Northeast India, and last month I bought a phone from a seller on Instagram who we were often customers of. The phone was an iPhone 16, and we bought it for Rs 54500/-, including delivery charges. Now the page is legit, and we have never had a problem before, as we have bought about 4 used phones from them already. The phone arrived, and that night we inserted our SIM card, but it couldn't detect any signal. We tried texting them about it, but they took a while to reply; this was a Saturday night. Then we rebooted the phone and even updated the software, yet the problem persisted. And we know it was not the SIM card, because it worked on other phones. Then Sunday came, and we called the sellers. They told us to send them the IMEI number, and we did, but then they went silent again. But on Sunday night, our local police came and said they had received a report from the Mumbai Police station. It turns out the phone was stolen and was "blocked" by the Police, so that when a SIM card is inserted into the phone, it will immediately alert the police. (I don't know the name of that tech). And on Monday, we went to the Police Station, explained our side, and came with the box and the charger, along with the invoice. And the police said the invoice can easily be faked. And the police checked the phone's IMEI through CEIR; it was indeed lost on the 1st of May and blocked on the 11th of May 2026. So the police told us it's better to file an FIR for cybercrime, and we did. Cybercrime blocked two accounts we sent the money to. The sellers were angry and at first said it was not stolen, but when we sent them the FIR report (the one from Mumbai that said the phone was lost), including a picture of the IMEI-blocked status from CEIR, they said they would refund if we unfreeze it. Cybercrime didn't allow this, saying that if they unfreeze the account, the sellers could empty it. Nowadays, one month has passed. We filed our FIR on June 8, and we haven't received a refund or any update. What should I do?