The disclosure we have is to return it within 10 days, however I believe that is in relation to 10 days from when you receive the replacement. I checked with some coworkers and it seems like the 10 days is to ensure our shipping team gets it checked in to avoid any unreturned charges, however you have the full 30 days to get it back. If it's closer to the 30 days, I would imagine there's a chance the fee will be charged then removed once it clears.
I have forwarded feedback on that though.
Edit: updated post