You may visit any participating Globestore to check the status of your Iphone 4.I belive they will check if what level or tier will your handset be. and they will be advising you how much it is .
as advised by the hotline peeps, new mechanics already apply for iphone forever plan:
** pay php10,600 for the cashout and choose any plan of your choice.
** on your 13th or 24th month, that's the time that you can trade in your existing iphone handset and upgrade to a new phone.
** no more tier
** Promo period is from January 15, 2014 to March 31, 2014