Copying from another thread for visibility:

I've forwarded the info internally and our team is already looking into it. I'll let you know more once I hear back from them.
Don't worry though, we will never charge anyone twice for the same thing on purpose. Anyone affected will get their issue resolved ASAP - let me know if you've experienced the problem!

Update! The issue has been fixed and we're now looking into resolving payment errors for everyone affected. Thank you for your patience!