If you're using the same exact account, then the issue you ran into was that you played after the import date on the PS4 then went back to playing on the PS3. As of the date that the import system imported your characters from PS3<->PS4, those characters were separated off, and from then on, any progress on the PS3 would not (and didn't) carry over to the PS4; any changes to the PS4 also wouldn't have affected the PS3. So, now that you're back to playing on the PS4, you're stuck with the characters you had initially because of the import. There is no fixing this issue and there's nothing you can do about it. The import process is a one-time-only thing, and as unfair as it may seem, it is what it is. If you purchase Destiny: The Collection, you'll at least get a level 40 Spark of Light to raise one character immediately to level 40 to get a boost, but anything nice and nifty you gathered on the PS3 is not going to carry over, that save data is entirely separate from your PS4 save data, and no, Bungie won't copy it over, nor will they refund you or give you anything free to counteract this. ------ If you're not using the same account on the PS4 that you had so highly-leveled on the PS3, then log in with that account and import the characters and they should be where you left off, but, again, that only counts if you've not already performed the import process previously.

Is Destiny trying to tell you something about your ability? Just asking. lol.