Unum denied reinstating my disability payments after I was diagnosed with arthritis

In 2006 I became struck with a near fatal illness. I was granted long term disability with UNUM as the administrator. I was back paid disability. I needed to get out of a bad marriage so I kept the back payment and understood UNUM would keep their payments 5 years. In these 5 years the illness has resolved itself but im now left with arthritis in my back, a bulging disc and other issues. UNUM has denied reinstating my disability payments. Now I am unable to get the medical treatments I need because I don’t have the money to pay for them.