Share your experience!
Hello!
I bought my SONY XPERIA C4 ON nOVEMBER 2015,
I've never experienced any problem with my phone BUt now I've started facing touchscreen problems after I perform the software update this May 2016. I did factory data reset and Software upgrade using XPeria companion but nothing happens.
I went to Sony Service Center today to ask for a repair. They said that I wasnt the only one facing C4 problems after the update 
They took my phone and asked me to wait for 2-3 months because parts needed for my phone is not yet available in my country ( Philippines). Now Im very disappointed to SONY that Im one of the c4 USERS that suffering from software/ hardware problems.
I'm sorry to hear that but there isn't much anyone can suggest other than stay in contact with your Local support.