Hmm I just faced this problem as well, I have RM52++ credit inside but I don't see any "long life" under *128*1*7# menu.

I'm however on DiGi Best Prepaid v3 though. But under *128*1*4# I only see change plan to "Digi New Best v1" and "Digi Smart Prepaid".

Update: Just called DiGi CS and "DiGi Best Prepaid v4" is no longer applicable (only for existing subscribers). My only option as per their advise, is to upgrade to "DiGi New Best v1", which they quoted to have slightly cheaper rates (I'm not even sure what's the current rate as this is my mom's number ; from 26/sen per minute local call to 20/sen per minute).

The upgrade is done via *128*1*4# and will be charged RM3. After that, I can see the "Super Long Life" option under *128*1*7# menu which will cost me another RM38 for it.