Bought PS3 Disc, upgraded to ps4, can't get ps3 license

[Nekodar]

So i can't just buy another ps3 disc? and go back to playing on ps3. because ps4 i've wasted months of time i paid for. and nothing works.

Not sure how it works if you buy another PS3 copy. All I meant is that you can't go back to your original PS3 copy since that was upgraded.
Aside from that, did you try any of the suggestions to help you play on your PS4?