So (I just want to make sure I understand you completely/correctly) you're saying the unlocked phone needs to have been unlocked from formerly those carriers? So a an unlocked Verizon phone won't work on Straight Talk for example?An Unlocked V30 should work fine on Straight Talk using AT&T or T-mobile.
You need to purchase a ST SIM card based on the phone original carrier. I.E. if the V30 is from Verizon then you need a ST SIM that works on Verizon towers. Search eBay there are a ton in that marketplace.So (I just want to make sure I understand you completely/correctly) you're saying the unlocked phone needs to have been unlocked from formerly those carriers? So a an unlocked Verizon phone won't work on Straight Talk for example?