What it might be happening is that you're playing a level and not doing good enough to get the 3 stars required to get the 1,000 nps.
Here's a table:
Brightvale and Faerieland Maps
# Stars Neopoints
3 stars 1,000 NP
2 stars 600 NP
1 star 350 NP
Terror Mountain and Lost Desert Maps
# Stars Neopoints
3 stars 1,350 NP
2 stars 850 NP
1 star 500 NP
My recommendation is to just play the very first level and repeat it 50 times.
You need to do only 5 moves and you will always get 3 stars and 1,000np in the page.
It's important to notice if your nps are increasing in the page.
And also important to know that GC resets the day at 5:00 pm NST
I don't recommend you to play other levels because it's a waste of time if you're not aiming for the amulet/backgrounds.