Did you get an email or text that said your phone is not compatible? If it was an email I think it is one they send to everyone whether their phone is compatible or not.
If you used this link https://www.visible.com/shop/compatibility and it says it is compatible you don't need a new phone. If it says not compatible it is possible your phone still may work. Visible seems to have dropped the ball on there IMEI number database and seems to have just cleared it of most Android phones sold before 2022. If your phone passes the checker you are good to go.
I received a letter in the mail that said upgrade mandatory
When trying to do the upgrade
It wouldn't finish
U'r live chat said there was an error in the process
I tryed it again & I got a screen that said the phone wasn't compatible
Again I chated with the live chat whom offered a supervisor to call me
That supervisor says they don't know when they are going to actually cut off the phones that don't compatability
I would at least like to know how much time I have till U cut my phone off
If it's immediate I need to figure out how to budget for a new phone if it's going to be a while then I'll get by with what I have
It seems as if the right hand doesn't seem to know what the left hand is doing
I think alot more communications need to be administered in this matter as to spasifics of what is going on with this matter
There is not much more we can tell you here in the forums other than what customer service has already told you and me. I am a customer like you and volunteer my time to try and help other customers. Late last August when the new plans/system was implemented they said within a year the old plan/system will be shut down. Don't know why Visible just doesn't put an end date and get it over with but it is coming in the next 3 to 4 months if they stick to what they said last fall. Sorry I can't help you any more than I have.
If getting a new phone is out of the question maybe try one of the cheap plans with Mint, US Mobile, Consumer cellular, there are a number of them out there now that offer $25 plan. I know they are not unlimited like Visible but maybe your only option when the time comes.