Power just is not what it should

First the good:
We have it in the bathroom, it looks good, the operation is simple, it is easy to clean.
When installed in a masonry wall, the sound is acceptable and adequate. If you build it in a plasterboard wall, a, it sounds rich and full.

Now the hook:
At first everything was fine.
However, the preset stations could be after a while no longer hear, it's just a single noise. First one, then the other. Even if I set the station manually.
I hear now in the morning and in the shower radio stations, of which I have fremdschämen me. I think that's crap.
What's wrong? No Idea.

Basically, this beautiful radio is useless, especially for the price and the cost!