Damaged Luggage and Delayed Responses

We traveled between Heathrow and O R tambo on the 26th March 2016. When we received our luggage at O R TAmbo it was damaged by the wheels and had been cracked. Which is very difficult to do being a hard case bag. On complaining to Emirates on the 31st March they said they are will to only pay me half of the bags current value and when I inquired further they fail to respond!