We provide our SMS service through a company called
Twilio. We pay for every SMS that flows through their system. They are experiencing technical difficulty with our number right now that must be difficult for them to track down. We've heard from a Twilio representative that they have "...a message in to our carrier again about this issue. I'll let you know when I have more information."
I know this is frustrating. We're just as frustrated as you are. Twilio has an incentive to keep our account working because we spend money with them when the number works. When the number is down like this they aren't making any money from us.
Our hands are tied here at the moment. We have a number of ways to add fuel-ups to the system including the website and
Fuelly Mobile. So you might want to try using those for a while until this is sorted out.