Who I have the same questioned this topic

How can you get a contact list from Backup Assistant (flip phone, LG Revere 2)  to the Verizon Cloud (iPhone 6s Plus). In the past, you could use the Backup Assistant app on the iPhone but that is now desupported... or you could go to the backup assistant website and download the contacts, but that is also desupported. Any other options? The Backup Assistant service is still running as of March 25... I just backed up the flip phone contacts and it said it worked. So how do you get the data out?