Not provided decision on our claim, just handed to their legal department who don't reply to our letters

My wife has been diagnosed with progressive MS. Discovery Life approved our claim and paid first installment for severity D benefit payment in April 2017. We then submitted required documents 2 months later for the next assessment. Her health by this stage was much worse. Discovery confirmed they had all documents to make a decision and would receive it in 48 hours. A week later we queried what was the delay and they said the matter was now with their legal department as we had not given them all the information when we took out the policy. We wrote back immediately and pointed out this was denied and incorrect as we had given them everything they had requested. Substantial communication followed and Discovery Life refused to provide details or deal with the matter. It has now been several months since we last heard from them.