Q: Help please...

Look here for help.

If you can't hear a person on a call or voicemail or if the sound isn't clear on your iPhone - Apple Support

Hi. Start from this page If you can't hear a person on a call or voicemail or if the sound isn't clear on your iPhone - Apple Support

This is a slightly different link than what Demo gave:

If you hear no sound or distorted sound from your iPhone, iPad, or iPod touch speaker - Apple Support

but maybe it will also help.

I Don't know if this will help either, but I ran into a problem on my iPad (I know we are talking about your phone, bear with me) where the volume level when using earbuds was very low and I could not adjust it to a higher level. The speakers themselves worked fine, but earbuds knocked the sound way down.

I Finally got it working properly by playing around and adjusting the volume limit in Settings>Music>Volume Limit. Even though I did not have it restricted, maybe you do, so check Settings>General>Restrictions>Volume Limit>Don't Allow Changes.

Having said all of this, it may be a hardware problem. Anything is possible, but you need to exhaust all of the software possibilities first.

Does music play OK and can you hear sounds in Apps with good volume?

At the end of the support aricle that I posted above, it says that if you tried all of the troubleshooting steps and it didn't work, you should contact Apple Support. That might be a good idea now.

If you've tried these steps and there's still no sound or poor sound quality from your iPhone, contact Apple Support.