There are only four "real" banks in Belize -- the two local banks, Atlantic, Belize, plus the branches of the international banks ScotiaBank and Barclays. Provident is just an offshore bank connected to Glenn Godfrey.
First thing to understand about banks in Belize is that you don't want to put more in a Belize dollar account than you have to. The Belize dollar is worthless outside of Belize and can't be converted. Most folks keep their money outside of Belize or at least in a U.S. dollar account in Belize.
You can have SS deposited directly into a Belize bank, but as of a few months zero Americans were doing that, according to the U.S. gov'mint.
Belize First Magazine http://www.belizefirst.com/