cheapest way to send package to Guatemala

We sent our dossier Fed Ex a year ago October and the attorney didn't recognize our name so he sent it back. The poor young man at the mailbox store was on the phone for about 4 hours trying to get fed Ex to redeliver. They tried again and no one was there... long story short.... Our package sat in customs for awhile then headed back to the US then finally made it there over a week later. VERY fusrating. Also, there is custom fees... we were required to leave a credit card # so they could charge us. That was also part of the problem b/c Fed Ex wouldn't charge us and kept telling the attorney he had to pay it.