MT#9481 API: set link from customer to balance

(cherry picked from commit 83bd0f93f2a2590053555a919b06c5e280b4fc72)
MT#9481 API: fix customerbalance link to self

(cherry picked from commit b9aa3be4ff136a3d7e62f6a6f76aa90d976e454c)
MT#9481 API: contract doesn't have link to balance

Removed on purpose.

(cherry picked from commit eced8fc589637766807f536d84deb72950ed9287)
MT#9481 API: use correct balance link

(cherry picked from commit 9dc97d1ed3844aa8e503c25448e87196ab165479)