First of all you need to decide whether you have Freeview or a satellite system. Freeview has NOTHING to do with satellites. It comes down your TV aerial. (BTW, satellites do not move position. So even if you did have a satellite system that would not be the cause.)
As a Matsui DTR2 is a Freeview box I'll answer the question as that.
So, as you have recently lost some channels, you should check your aerial and its connectors.
t
October 2008