AfterShip Returns & Exchanges

I haven't used the app yet. I actually launch my website today so I'm hoping it works well. I have the forever free plan but i'm confused about what happens if i get more than 3 returns for the month. Will i be charged?

So it's been a little over a week since I have launched and when I tried to create a return for the customer it says that the items are non-returnable even though they should be eligible.