Bruno
First, I would verify the SIM chip. . .I would place it in another cell phone to make sure that it functions OK. It is possible (but very unlikely) that your carrier uses the IMEI number on your device to track 'grey' market devices. GSM does have the ability to restrict network access based on IMEI number but to my knowledge, no one is really doing that (but there is always a first).
Otherwise, try reloading the 829 software. . .
Good Luck
Phil