help! box has mixed all channels up?

before it went;
1 bbc1
2 bbc2
3 itv
4 channel 4
5 Five
6 something
7 something
8 something
etc, i remember
19 being dave etc
20 virgin
21 viva

but now they are all in the 800s and theres radio channels mixed up with the programmes!!!
How can we return it back to the original order!