In May 2020, EventMaker changed its database provider for city and country information. At this time, all existing event locations were converted to the new data scheme, and it is possible that the conversion led to your FIBA 3x3 event having a location, which is different than what you entered yourself.
If the event is in the future, and you can still edit its data, just go to EventMaker tab Overview, Edit Location and enter a new location.
If the event is in the past, and its data is locked, the easiest way is to write to Customer Support via this form . Remember to include the URL (web address) of the event from https://play.fiba3x3.com/events directory