Samsung Galaxy A3 (2016) — Galaxy A3 2016 wont make or receive calls.

Hi, I bought this A3 2016 secondhand. Its a lovely phone, But it would not make calls or receive calls, I didnt try to use it straight away so I didnt know this when I bought it. It keeps dropping the signal, saying No Network Connection, signal seems to fluctuate. Occasionally is will ring on 3G.. but it wont ring at all on 4G. When I go into SIM Settings, it says Network State Disconnected, Even when it shows a connection, it does not show my number and will not make a call. Incoming calls go straight tom Voicemail. I got a new SIM, still no joy. My SIM works fine in other phones, other SIMs wont work in mine.. I Checked the APNs and they`re fine. (Vodafone). I thought Android was the problem. I rooted the phone and installed LineageOS 18.1. It still wont make calls. Im at a loss. Wifi and everything else is fine. Its a lovely phone. Could it be a problem with the internal antenna? Any ideas please? Thanks in advance.