Sudden loss of volume

Hello,

I have been wearing an Oticon Tega Pro for about five months. It's been working great up until a few days ago when the sound started to fade out. I initially figured that the battery was probably going dead however, I never heard any of the beeps indicating a dead battery. I tried a new battery but saw no improvement. There still is some sound but it's not anywhere near what it was. When I cycle through the settings I hear a very faint beep. Also, when I adjust the sound the beep that indicates the optimum volume level is also very faint where it was previously very loud and clear. I can't hear nearly as well as I could just a few days ago, I would guess it's about 1/4 to a 1/2 the volume of what it was. I thought maybe the ear mold was plugged so I cleaned that out as well but theres still no change.

So these are my questions:

Do the hearing aids themselves need to be cleaned? I've never cleaned them before but I don't know if they need to be.
Could it be the earmold? The one I have is old, about 4 years.
If the aid is defective or damaged, does anyone know approximately how long and how much it would cost to get it repaired? I got it for free through a friend of my brother-in-law who is an audiologist so I don't have warranty on it. He lives about 1000km away so I can't go to him to have it checked out.

If anyone has had similar experiences or knows how to solve the problem, I would greatly appreciate your thoughts.

Thanks very much!