Remote Control ((SR30-S1B)) won't change channels!

Our remote control (SR30-S1B) for our Samsung TV does not change the channels.  We may get lucky & after ten tries the channel may change, as long as it isn't a HD channel.  The remote will never take putting in 4 digits.  This has been an issue since we got the TV 8 months ago.  I have three other Samsung TV's & have had no problems with them.  This TV is on the wall & the cable box is behind it, but we should still be able to change channels.  We did all the troubleshooting with the remote, resetting, changing batteries, new remotes, etc.  We have had ATT & the Geek Squad out many times.  The most recent Geek Squad visit rep. told us we need the newest ATT remote control that has a something that plugs into the cable box via USB.    Anybody know anything about this remote?  I can't find it online to order it, but it did come up on my TV when the Geek Squad guy was trying to help.