Please Help! My parents' B2 application is on hold, can congress

My parents have been in US 3 times in 2002, 2003, and 2005. They extended stay from 2003 to 2004 with approval, and with the original copy of approval notice, they got visas easily in 2005. Somehow, the original approval notice could not be found this time, when they brought the copies to the interview on 10/30/07, the VO said he needed to verify the extension notice and kept passports and all application documents. He said they would be notified in a week. But 2 weeks have gone, still no response.

My question is:

1. Should I conatct a congressman for help? If so, how could I find one?
2. If anyone has a template letter to congressman, could you please share with me? At least get an idea how the format is.

Thank you very much in advance!