I don’t know for Gotv but for startime,
With the phone number connected to your gtbank account, dial *737*37* Amount*Smart Card Number#
You can conveniently read more on payment methods of startimes recharge. The amount should be the cost of the plan you wish to subscribe for. The smartcard number is the 12 digit number on your Star times card.
To authenticate payment, enter the last four digits of the gtb Naira card.