Sony Xperia M2 Aqua Repairs

Over Christmas my phone fell not even 10cm and the screen cracked.<br> Sent it in for repairs under warranty to be told that a waterproof phone is water damaged.<br> All that is wrong with the phone is the LCD screen needs to be replaced, everything else works perfectly.<br> Please explain how such a small fall would crack the screen and where exactly the water damage comes from.<br> After a lot of back and forth still no luck having the phone fixed.<br> MTN & Sony lack of service is pathetic.