You should anticipate that as how your relationship with any non-big name service you use will end because that's how it will. It just won't be working one day, then the next. You'll hit the internet to find that the person running it died a month ago and the business with them.
I imagine a lot of those companies ending is the result of acquisitions/mergers where the services continue uninterrupted and in the vast majority of cases where that isn't true, there's a warning that it will end.
(Granted, not an S&P500 company, but those have been known to fuck up as well)