I feel for you there matey!!
When i have come across that, you always get a customer who thinks your actually making up the word Wideband

, sometimes there is no convincing them that their aerial needs upgrading, no matter how hard you try
I to have that problem from time to time. Normally i run the box through the manual setup, providing you know the channel numbers (freeview)for your transmitter. That normally works for me.
How was the other channels? any pixelation?.....seems strange that only 1 and 2 are missing.
Sometimes also its normally a glitch in the box.....unplug it from the wall socket scenario!!!!