I haven't tried it yet. I'm guessing either via their website or call customer services. I've just been living with it so far. Out of interest, for those who have this issue: did it always have an issue, or did it one day stop working? Had you been playing with settings or connections to your TV before this issue became apparent?
I'm having this same problem, however, my tv will not allow me to agree to the end user agreement in order to generate the pin to get an agent to remotely reset it. As someone mentioned in the comments, this started when I connected the smart things app.
I have the same problem and also was not able to agree to the end user agreement to generate the pin for remote assist. The online assistant said they will get someone else to help in next 24-48hours. Where they able to get this fixed on your end?