how do i get it back? I am the developer of it and for several years it was on the App Store I is my copy and has vast amount of information in it that i value
suddenly notified that my app is "no longer available " when apple 15+ years ago told me it would always be available
Pleae provide information, it is not clear what you are taking about.
Is it an app you developed ?
Is it an app you purchased (which is it ?) or a system app (which ?)
Which platform ?
Could you also the exact Apple's message ?