The past few weeks people trying to phone me have been regularly getting busy tones and going straight to voicemail, I'll then receive an SMS later on informing me of the missed call but only if that person successfully calls me after the failed attempt? My signal strength does seem to be up and down but usually it's around 3 - 4 bars but has went as low as 1 bar. Orange on Twitter say there are no problems in the area but I've usually had good signal strength so not sure why this has started happening all of a sudden. Anyone else have this problem? I've enabled call forwarding for now to my landline and switched my phone off!