Voice call quality extremely low while mobile data is off

Anyone else having issues with voice calls on the dual sim version? My gf has got the motion and I can barely talk with her on the phone as the voice call is an absolute mess, the quality comes and goes while standing in the same spot and having data turned off.
Is this a hw issue? Has anyone else experienced this issue on the dual sim version or single sim?

I have BBD 100-6 (dual sim) and BBD100-1 and use both with data turned off (particularly when roaming) but I have never experienced your issue. Sound quality has always been very good.

Originally Posted by JRCollie

I have BBD 100-6 (dual sim) and BBD100-1 and use both with data turned off (particularly when roaming) but I have never experienced your issue. Sound quality has always been very good.

Ty for the reply, I'm curious to see if anyone else has this issue or it's just the phone my gf has.