Perhaps email and explain - have they accidentally sent you two? If so, you want to keep the unlined one as that's what you ordered. You've used the lined one because that's the one you got sent first, and you didn't know the difference back then. Do they want to pay for you to send back the used lined one?

If they did send you two accidentally, it's their mistake, you shouldn't incur any costs from that, the unlined one is yours, it's the one you ordered. Fingers crossed they'll just cut their losses and you'll get to keep both!

What's news in the nappy world? Are there any new nappies around or any good sales?