Hi gaia108,
Good news is, if your Beats need service you're within the one-year hardware warranty. To start, have you tried cleaning the ear tips?
If the issue continues, test a reset of your Beats. (Assuming this is not what you did when you stated you reinstalled the device). The article here can help Reset your Beats earphones
Specifically the section quoted below.
"Reset Powerbeats Pro
- Place both earbuds in the case. Leave the case open.
- Press and hold the system button on the case for 15 seconds or until the LED indicator light flashes red and white.
- Release the system button.
The LED indicator light will continue to flash white, which means that you can pair your Powerbeats Pro with your iPhone, Mac, Android device, or other device again."
We'd also recommend testing the issue on another device or with a different app to help isolate. If the issues continue, check out your service options using the link below and contact Apple Support for further assistance if needed.
Beats Repair - Official Apple Support
Contact - Official Apple Support
Contact Apple Support
Cheers!