Has Channel Freq's Changed ?

Hi, just wondering if any more of you guy's are experencing probs with channels disappearing ?
I'm using reply lite here and earlier I noticed some channels were no longer working so I decided to do an automatic scan starting at 291.00 and ending at 419.0 and it found most of the channels but it didn't find the one that were originally not working. I then done a manual scan for S*l sports 2 on 355.5 but nothing and I also tried some other channels such as BB*1 on 347.5 and C*4 on 347.5 and it came back with nothing found.
Just wondering if the channle freq's have changed or have I got a weak signal.

thanks