O.k then it looks like we are at a point where a remote may be necessary.
I could find an original remote for you but I can also tell you that a RCA universal remote will work as well and usually they are already pre-programmed for RCA TV's .
Another option would be to call some repair shop in your area to see if they might have an RCA remote that was left behind and that they may sell you cheap like 5 or max $10.
I can tell you that all repair shops have boxes full of old remote and RCA was definitely a popular model .
Also the fact that it doesn`t have to be the exact remote , pretty all rca tv remote will operate any model of rca tv.
If you want to have a list of repair shop in your area , enter your zip code at the link below ;
They probably will ask you to bring in your old remote for comparison if they have some.
If you cannot find one that way then you still have the option of a universal remote , usually places like walmart or bestbuy will have RCA universal remotes or I could find the original for you.
Hope this help and please take the time to rate my answer if that does the trick , otherwise do not rate at all , just let me know and we`ll see what can be done.
Note that you can reach me here at any time after rating if you have questions or still need help with your direct tv box.
By the way , not sure what the direct tv people had you try but I would unplug the box`s power cord for a couple of minutes to reboot it before or after you have the tv set to the correct input.