Q: call out ringer volume low

Hi Angie, 

Sorry to hear about your issue with your iPhone with the sound from receiver not being loud. I can provide you some troubleshooting to get it sorted out. 

I would start with taking a look at the article below to walk you through looking to see if any Bluetooth devices are connected as well as cleaning out the receiver for anything thing that could be degrading that sound. Also make sure that your iPhone is up to date with its software as well. 

If you can‘t hear a person on a call or voicemail or if the sound isn‘t clear on your iPhone
https://support.apple.com/en-us/HT203800

Let me know if this helps. 

Have a good day