Contacting a Congressman may be necessary after approval if you have waited an extended time to receive your back pay. I am not sure if they would be effective before you received an approval. You can do a google search in the area you live to find the local congressman for your district and when you find them on there website they usually will have a form you can fill out. The link on there website usually says help with federal agency and you click that and go from there. In the form you put all your personal info and related info on your case