EXCON Letter - Bank is Clueless

I bank with FNB and i need an Excon Letter for my Nedbank Home Loan Application. Called the bank and was transfered from one department to the next, including the Forex department where i was on hold for close to an hour and still got no assistance. Visited the branch and no one has a clue what an EXCON letter (basically the entire bank doesnt know what it is). Who can assist me on this???