The cache is not at the posted coordinates.
This cache replaces GC7JMEQ 2G or not 2G. The final of this cache is at the same location.
When calling Norfolk Island telephones from elsewhere in the world you must dial a different country code to that of Australia, and a single digit area code.
To solve this puzzle, you need to find both the Norfolk Island country code and area code.
Call these numbers ABCD. You will find the cache at
S29° 01. (B-C) (D) (B-A) E 167° 57. (D) (A) (A+D)