I have a 3310 firmware 04.06 nhm-5 and im having trouble with reception, it has service bars and a full battery but sometimes I make calls and it does 3 beeps and doesnt let the call go through, this also happens when im speaking to someone over the mobile, the audio quality is also poor when this happens. This can happen up to 10 minutes (the longest ive had it happen). Also I cant send sms's when its happening and people cant call me. It is not my service provider the problem can be reproduced on 3 other service providers (optus telstra and vodafone). I have also reset the phone, I am hesatant to flash the phone unless theres something else I can do insted. Any ideas on what may be wrong?