I work on a ISP in Africa. Our customers were being redirected to Google cache in South Africa. Apparently with no reason, they start being redirected to Google US, which for us has higher latencies (avg: 400 ms).
How can I contact Google to fix this DNS Geolocation issue? Or, what can I do?
Your experiencing issues with google's GEO IP tool; you can fix this by going here where you can register your companies IP block with them and they'll fix it.
Have you attempted to contact Google's NOC regarding this issue? As per Google's PeeringDB records, they can be contacted at noc [at] google [dot] com
Jacob already linked to the correct place to get Geolocation data fixed.
Geolocation is done based on the address of your recursive DNS resolver, and not the IP of the host running a web browser.
Due to this, a workaround for this problem is: