Top Up TV Anytime Help

I'm having a strange problem with my Top Up TV Anytime box. The box has two tuners built in, but for some reason one of these tuners isn't working. The one tuner that is working is for when the box first starts up, so when i change channels I can't view them.

I know it's not an aerial problem as I've tired several different ones to no success.

I've tried tuning in my box again but no channels are picked up when I do this.

And I've also tried uisng different tuner frequencies, but nothing is picked up no matter what frequency I use.

So what can I do? Is my box broken, or is it something simple that I can fix without too much trouble.