<< The sound does work with the phone's speaker so we are thinking there is some setting blocking it and it may be with their router rather than our phones. >>
If the sound gets to your phone, but refuses to play out the { MFI Hearing Aids, Phonak or other non-MFi bluetooth Hearing Aids, Bluetooth Headsets, similar devices } that sounds to me like a shortcoming of the Listen App.
You could cut the hearing Aids out of the loop by testing with name-brand Bluetooth headset.
Do you have/ can you find (through a local audiologist) anyone with Resound hearing aids?
I mention Resound because Resound Smart-3D app is said to be the best App there is for connecting hearing MFi Aids. If Resound hearing aids can work, then maybe you can embarrass/pressure Listen.
Either that or simply threaten to send all the Listen gear back unless they provide some real technical assistance.