No sound on my mobile phone

I had the same problem with a Samsung as well, the shockproof and waterproof model for sports and all that...
The ringtone worked but I couldn't hear my callers

I solved the problem simply by turning off the phone, removing the battery, and putting it back in.
It was probably a bug and needed to be reset

There you go, I don't know if it will work in your case, try it if you haven't already.

Hi everyone.

I had exactly the same problem, I had a Samsung S8300. No sound at all. So I took it to Orange and they told me that it was a dead part. Since my phone was one year old (so out of warranty), I downgraded my plan to the minimum (for those who are with Orange, 12 euros) and I went to SFR.
Before that, I had sent my phone for an estimate, the bill exceeded 100 euros.
I hope I was able to help you. Bye

I had the same problem with my Lumia 800; it's the headphone jack that malfunctions due to a loose connection: the phone thinks there are always headphones plugged in and blocks certain sounds due to dirt stuck inside. You just need to clean the headphone jack with compressed air (available in the electronics section of supermarkets). If that doesn't work, you need to take it to an authorized operator or shop so they can dismantle it and clean everything properly (to avoid losing the warranty).

Good luck!