You also need to take note of GOMO port out terms and conditions.
15.
Termination/ Port-out Service
i. Termination of the GOMO Mobile Plan via 24/7 chat agents, GOMO mobile app, GOMO Website or
port-out process must be started at least 3 days before the next scheduled recurring payment date
. In the event the Customer initiates a termination of the GOMO Mobile Plan less than 3 days before the next scheduled recurring payment date, the Customer will be charged for the next recurring payment.
ii. GOMO Mobile Plans that have been successfully terminated, cannot be reinstated for any reason.
https://www.singtel.com/content/dam/gomo/GOMO_Mobile_Plan_TnCs.pdf