Problem with freedconn t com helmet communication system

I have been using these devices for more than 3 years and they have proven very reliable.

Six months ago the devices started malfunctioning.

And they only malfunction when I use them/connect with an iPhone.

on two different helmets with two different devices the same issue occurs.

when I make or when I receive a call, on the other end the person cannot hear me,it keeps interrupting my voice.

everything else works, Siri , voice commands etc.

I have tried to check on the settings of the iPhone, but I can’t find anything.

Has anything similar happened to someone and could help?

thank you.