check out
mazda6club. com and what happened to your antenna wannabe? Sorry to jump off topic with the antenna thing.
I've read about the keyless thing and they talk about moisture getting into the buttons on the outside is what is causing it. Some say that the buttons don't work right away after washing the car but in a day or two they start working. So if your car is getting wet from rain or snow lately that could be an issue.
As far as the interior buttons such as windows not working you can reprogram them yourself. I'll post it but don't know if it's worth it.
Put your key in the ignition turn it all the way but not to start then roll down the drivers window half way the all the way up and hold the button for 2 seconds, then do the same to each window by using the window controller at that window, don't use the drivers controller. Then cycle the key off and on again and the interior buttons should work again. I'm sure this wasn't the issue but worth a shout out on it though.