Hi @ChaiChen ... I feel sorry for your situation right now but this thing I learned with their system upgrade...
It seems that an account cannot be modified unless a previous window (or recorded concern) is closed by the very person who opened it. Based on your accounts written on your Facebook page, you've had several issues in the past which may not have been recorded as resolved or closed by the person who opened it, therefore the change of plan and moreso the activation of the sim and the 1 month adjustment cannot be processed causing a lot of delay.
Several account modifications could be done all at the same time in the past but it seems that this is not possible with their present "upgraded" system maybe due to security reasons and monitoring purposes unless a higher authority or a higher support team manually closes it one by one upon manual verification. Call it a transition stage where even the CSRs are trying to adjust how to work with the new system more efficiently but I do agree that it is causing a lot of irritation with Globe's present subscribers.
I am hoping too that this problem is addressed sooner than later.
To help address this more systematically, I suggest that you ask the hotline what windows are still open from the earliest to the latest and to concentrate all efforts first to closing the earliest window before making another follow up with the next one and so forth until they close the latest. Make sure to document the case/reference numbers of these reports in case it is elevated to a higher authority.