FYI, you are talking to other fios customers here. Sometimes fios will esculate issues on here though.
As far as the problem, Fios didnt promise anything. You simply just took ones word. Did you not ask to see the terms of service you were agreeing to before switching?
People need to research things themselves instead of just believing ones word these days. With google there's no reason to not look things up. Getting things in writing or being able to print online is also a good idea.
Pandora is on the old dvr's but not the new media servers. I'm sure it will return in a future firmware update.
There's always Roku, Amazon Fire TV, or other devices such as screen mirrioring cell phones to a tv etc.. to get Pandora.