Charged for something they should repair free

I'm a Cellc contract customer. I sent my device to one of the Cellc stations for water damage three months back and my phone was covered for such as it had ADH (Accidental Damage Handling) but I was surprised when they called informing me that my phone also has a cracked screen and I need to pay an amount of R2648.00. What I know is that I have signed an aknowledgement form stating that my device was in good condition when I booked it in at Cellc Soshanguve crossing. I then sent an email to their complaints department about the situation and they rep**** telling me that a superior will call me from their repair department, that was 2 and a half months back and nothing has happened. My device is still with them and no one is telling me nothing. Ref number: ***