I used a Wild card, but my collection is not complete!

That has an explanation! You may remember there are 2 types of wild cards: Special and normal. For more information, you can check this article

Whenever you use a normal wild card, you will see this display:

You can see you can take 3 cards for the Solid plans case, but there are 4 missing clues left... So what's the deal?
This means you still need a special clue.
Special wild cards will let you take any special clue, which are different since they have a golden frame, like this:

Now you can see that there are only some cards displayed to choose from with a golden frame, but if you check the cards left to complete the case and the cards you can pick, you can see that the numbers don't add up. That's because the rest of the cards are normal clues waiting to be discovered!

You may wonder what if these cards are colored when I use the wild card?

Then that means you got all the available cards the wild card can offer you! Most probably you got every normal clue. This way, the wild card can only offer you the cards you already got to get more duplicate stars. Which can be exchanged for additional extra energy and card packs.