Appeal

Could you help with this issue? What is the best way to write a letter to the MSEC Chairman requesting an official document. The fact is that my documents were returned to MSEC with the following words: “there is no basis for the disability group.” (written by the chairman of the regional MSEC). Without seal and signature. What is the best way to make a request for an official refusal, so that later you can challenge their decision? Thank you.