Bounce tracking and messaging not working with LTE but does on wifi. In Australia

We purchased a Bounce watch and a LTE subscription for my son last Christmas(2024) at first it seemed to work rather well, except for the lag in the live tracking, we could message back and forth and I knew where he was by getting notifications when he is crossing boundaries that were set. recently this has all stopped working. When he is at home and the watch is connected to WIFI the watch syncs and all messages that were sent when not connected to wifi get sent and received, and notifications come through ie watch is charging or disconnected, powered off etc.
I have tried to reset the watch, removed the app from my phone and re installed it, re connected the bounce to the app and nothing seems to work in getting the LTE subscription to work. On the app when i go to my sons account and settings under connectivity it says it is active. We are finding this frustrating as the subscription and watch is not cheap, hasnt even lasted 11 months and issues are being had. We rely on this with our sons medical history to know where he is at. Any assistance in getting a solution to this will be greatly apprecitive.