Unlocked GSM iPhone Says ‘No Service’

Hello , I have recently bought a GSM Unlocked iPhone 7plus (Off Amazon if that helps)

However , I know it is unlocked as it will let me change APN settings and select a network it has a list of ‘Sprint , Verizon , T-Mobile, AT&T, and HOME’ at first it was saying ‘HOME’ in the top left of my screen , only sometimes getting a bar or two and I was able to make and receive calls, no data and can’t send text, and the calls will only work if I turn Roaming on and under Cellular Data Options I click LTE, voLTE. Still saying ‘HOME’. I somehow got the phone to say “Update carrier settings” , I did it. and it started searching and carrying on, It’s been about a day and it’s just saying ‘No Service’ I have plenty experience with iPhone’s I used to work on them , But I have never seen anything like this ! Was i scammed ? Did i buy a false unlocked iphone ? could it be the sim card ? Just posting to see if anyone can relate or has a resolution, Thanks :)