Unitron hearing aids shut down when receiving or sending texts, taking pics, or any type of notice

My left hearing aid will almost shut off/ much lower volume then back up when getting or sending texts, taking pics, scrolling through FB and a video is playing until I scroll far enough past it. It is very annoying. It appears as even lower volume than if a phone call were coming in and both aids block out background noise. It only does it with the left aid. It took the dealer months to get the background noise issue resolved where both aids would go substantially lower to the point I couldn’t hear a conversation in my car. Customer service from the dealer has been terrible from the start. They gave me a phone number that deals with phone settings but they were all correct. They tried saying as they are paired only one will react and send signal to other, yet I’ve told them many times only one goes down then back up. They now are telling me there is nothing they can do although I suspect nothing they are willing to do.