They can ignore the letter. The committee could then issue a subpoena to force them to answer questions. Uber could refuse the subpoena. If they did, Uber co

They can ignore the letter. The committee could then issue a subpoena to force them to answer questions. Uber could refuse the subpoena. If they did, Uber could be held in contempt of congress. But, that would require a full vote -- which seems very unlikely. Hilariously, the last person to refuse to testify before congress was an IRS director (Lois Lerner). She was held in contempt... and then nothing happened whatsoever. Congress's real power is to pass laws. Franken won't be doing much of that with the Republicans in control of the Senate. I wouldn't be shaking in my boots if I was Uber...