Lowes acct disconnected for nearly a year

It has been more than 10 months since my Lowes Business Advantage account through Synchrony Financial (https://lowes.syf.com/) has worked. It worked for over a year previously with all the same login info, but then stopped. I have not been able to reconnect it for 10+ months nor create a new connection. Customer service has gone as long as 3 months without replying and when they do, it’s usually that I need to just refresh it. Over a month ago I was told Stessa was switching their backend provider. It still doesn’t work. Any suggestions – either to fix it, or to get Stessa to take my request seriously?