Lumenvox and Cell Phones

We are banging our head against a wall trying to get Lumenvox and FreePBX to play well together. Quite a few times a day when someone on a cellphone calls in, no matter what name or department they say, the beginning of the IVR starts over and over again. Sometimes it will just route them to the wrong extension all together. Anybody know how to get this working as it should?

Have you elminated the possibility that they are calling from a noisy environment?

It happens with multiple callers, including myself from within my SUV parked with no background noise.