I joined Visible a few months ago along with 2 others. I have a Galaxy S8. My S8 is acting up, so I purchased a remanufactured S8 that is Verizon compatible. Now I am told the phone I purchased is not compatible. I think Visible wants me to purchase a NEW phone from them. I cannot afford a new phone. I am retired.
Did you use the IMEI checker, the compatibility list here: https://www.visible.com/help/compatible or plug your old SIM in to your new phone?
Some people have had the checker say a phone won't work, but plug the SIM in and it does.
Mobile phones has modems that connect to certain bands which are defined in the specifications.
For example the Apple iPhone has different models that are adapted to the mobile networks in different countries. The point is the same S8 could have been made for a different country, not for USA.
You could use the IMEI checker tool mentioned or simply plug in the SIM to see if it works. If it doesn't work then you may have to find an alternative mobile phone to make it work in Visible.
Or else you may have to move to a different network.
From what i recall (from my memory), Visible only connects to Verizon's LTE and 5G network. No 3G, No 2G (if any left out).
P.S: If this helped you, please mark this answer as solution.