1-877-762-8762
Emails usually generate an automated response and nothing further.
Snail mail goes to a place where it is tested for contaminants and takes a very long time to arrive.
Using the toll free number is the best. Just about every office actually answers their phone. Sometimes you get voice mail. McCain's office has a spin....they say they can't talk about anything relating to campaigning, campaign donations (such as VIACOM) and give you another number which just loops you around and hangs up on you.