SOLVED
I have microphone problems. My mobile is 2, 5 years old and when I am calling the other participant (another person) can't hear me. I hope you understand my English since it isn't my mother tongue. Thanks for your help. 
Hi @oureli, welcome to our community!
I am sorry to hear about your phone. 
Based on the troubleshooting that you have already done it sounds like it's related to hardware rather than software, however there is a few more things that you can try!
First of all, could you please test the ear speaker in the inbuilt test in your phone? You can find the test in Settings > About phone > Diagnostics > Test > Ear speaker, can you hear the sound being played?
If you can't and to completely rule out that this is caused by the software in your phone a software repair using Xperia Companion is the next thing to try.
Performing this repair will remove all data stored on the internal storage of your phone so creating a backup using Xperia Companion before starting with the repair is advised.
Let me know how it goes!
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