Consistently open and interact Google maps while connected to the network in question. Google reports back the GPS/Neighbouring wifi AP's location, from that IP address. This is likely how they identified the IP was incorrectly in Central American in the first place
That along with reporting the incorrect geoip data to google should clear it up over time. However I have seen this take from 1 week to 2 months to improve. The more users / devices using Google maps, the better chance you will have with Google auto correcting the location.