complaint regarding fixing of cellphone

I took my daughters cellphone to Vodacom in Tygervalley. The reason taking the phone because it does not want to charge. The girl who helped me did not know what to do and she asked the guy in the shop what to do. I explainted to him that the phone does not want to charge, and he showed her that the place where the charger went in shifted. The phone was booked in and after nearly a month I phoned them as I did not hear anything from them, they informed me the phone has liquid damage and it will cost me R1300.00 to fix. I rejected it and told them that the phone did not have any damage, and send a complain to Vodacom. They did nothing. I took the phone to another supplier and the phone was fixed for R190.00. How can they fix a phone with water damage for R190.00.