Charged for cellphone that is not fixed

Good day,I bought a Blackberry 9320 cellphone in October 2014.My wife took a cellphone to H&H because it went dead.She gave the phone to one of the sales consultant who said he will take the phone back to MTN for repairs.One month later we were told to that they discovered traces of water inside the phone so we need to pay R350.00 assessment fee that wasn't explained to us.We were not given any paperwork to sign that will explain that there is a certain fee that you pay.I have submitted my complain to Shoprite head office on the 21 may 2015 to Margaret Hill who promise to come back to me after investigating.This morning I received another call from Festival mall branch to come & pay R350 that is needed in other to get the phone back.I still pay for this phone which is still with the shop for the last 4 month now.<br>