Speaker fails after one month - have tried three phones!

This Panasonic model was selected b/c we needed one at work with 2-line capability, and based on previous experience with Panasonic cordless phones, we felt a Panasonic would be good quality. Unfortunately, we are on our third phone of this model. The speaker/ringer has failed each time, after one month or two. The first phone was purchased in Dec 2006, within 30 days, you could barely hear the ringer. We exchanged it at Best Buy and decided to purchase the extended warranty. The 2nd phone was acquired in early Jan 2007, the same thing happened to it after about 6 weeks, but I noticed not only was the ringer volume bad, but the speaker in general was bad. We placed the 3rd phone into service about March 2007, and I've just realized that there is no ringer or speaker at all... at some point it went bad and we did not notice.

We do not abuse this phone. We do not even use the speaker phone in our environment, but it seems to be the same speaker as the ringer. The phone is sometimes exposed to sporadic loud noises or constant low noise, but I don't know if the speaker could be affected by it.

I've inquired with Panasonic about this problem, and they claim there is not a known problem with these phones. I am sure glad I bought the extended warranty, and I plan to take Best Buy's offer to try a different brand phone as the next replacement.