Unable to hold to what they advertise and promise

They claim that the Sony Z1 Compact is waterproof. Mine was until the screen was cracked and replaced by Vodacom for a fee of R2300. After repaired it fell into a basin of water and went black. It was sent again to the advanced repair centre. After 2 weeks while receiving sms's about he repair process I was informed that it was not economical to repair. Neither Vodacom or the Sony advanced repair centre are willing to sort out this problem. The phone was waterproof until the screen was replaced. The advertise the Z1 Compact to be waterproof but after repaired it wasn't. I feel that Vodacom is responsible to sort out this mess because my contract is with them. i would like to have feedback regarding this from them. If not then I will take it further. I have been a vodacom customer from1996 an a Sony fan all my life. It makes me sad that nobody wants to take responsibility for this matter. My poit is that it wasn't waterproof after the screen was replaced.