Hi @6pengliu, we can see that the issue has been escalated to our Engineering Team and this has been lodged to Telstra.
Telstra has committed to send a technician anytime between now and 29/May/2019 to investigate further.
The case engineer is closely monitoring this case and will contact you as soon as an update is received from the technician.
Should you have further queries, please let us know. Thank you.