Thanks for being with globe.
For aftersales concerns regarding device repair, it would be best if you could consult at any Customer Service at any Globe Business Center nationwide.
Since it yous sleep/wake/power button that is not working, I believe you will be referred to the nearest repair center (if there is any in your area which the customer service rep will provide you), or they will refer you to call a specific number where they will be giving you a code so you could drop your phone by at the nearest drop-off point who will deliver your phone to the nearest repair center.
If your device warranty has already expired, I believe your concern could not be handled by the store anymore. However, you may proceed to the nearest Apple Service Center nearest you for the repair of your device. It is also your discretion if you would have your phone repaired by any third party service centers.
Then again, please visit the nearest globe store so your concern can further be addressed to the right channel.
Thank you and best regards!
bring your unit back to the Globe Store and have them check your phone, they might have to send that to the manufacturer.