I have bought Nokia *.* plus in month of April for * to *.* months it worked best then...

I have bought Nokia *.* plus in month of April for * to *.* months it worked best then it started troubling me then i took it to Nokia care center they updated the software and gave me back again after a while it started behaving like earlier then when i again took it to Nokia care center * days back they told me that water has been detected in your phone but as far as i know i have not taken my phone to any place where it can come in contact with either water or sweat now they are telling to change the charging slot and display for worth *K now you only tell for saving money for alomost * years i have bought this phone as i trust Nokia from a long time so why they are treating me like this please help.Another thing i want to tell you that how can a charging point can rust from inside either the water must continuously go at that place or the phone must have been fallen in water but both the cases has not happened with me and now they are blaming me only.