Poor service

I went to a specialist on the 25/8/2015. Dr Johnson. I submitted the claim with all the necessary documentation. Did a follow up on the 29/9/2015. Phoned in Nov, Dec and Jan. Said the claim is been processed. When I phoned in Feb they say the claim is decline because I submitted is 120 days after the service was rendered. I have all the proof that this is a lay. I send them the proof and up until now no feedback. My claim for the 8 Dec 2015 is also still outstanding. Get no response from them. Please can you help me.