I don't think that it is the VA. This number is not listed on the VA, Missouri web site. Someone left a message with my wife stating that I was over paid $5,000, not true. I have not been able to get an answer when I dial the number.
This number is the St. Louis Regional Office of the Veterans Administration. And yes, sometimes they will call on saturdays. They are sometimes working O/T on saturdays, trying to get caught up. If they call you, they usually have a question about your claim or they may be wanting to schedule you for an exam etc. .