Hello,
Starky Halos works fine on IOS 9.3.1.
If it still doesn't work for you, do the following.
Connect your iPhone to your PC using a USB cable.
Launch iTunes if it doesn't open automatically.
Perform a device backup.
After the backup, restore your iPhone to factory default and set it up as a new phone.
Pair your Halos by going to settings> General> accessability then hearing aids.
Once paired, test it by placing phone calls and listening to music.
IF all is good, you can install the Trulink app and whatever app you use.
Note: If you restore from backup, the problem may reoccur due to a corrupt file or rogue app.
HTH and good luck.