It sounds like a refurb machine , which they reset to fix it and it has loaded Win 8.1 from the NOVO backup partition but is still stuck , which means it's a few years old I'd assume..... it may have a bad HDD or something? but I'd say the Vendor lied as it wasn't tested thoroughly.

I'd also goto Lenovo and check out my Warranty status etc ...

You sometimes have to look real close for the Novo "Button" it is sometimes just a hole for a paperclip , with an upside down U next to it usually.

Officially the update to Win10 is no longer free , but YMMV , especially if it once had Win10 on it , then it will already have a valid Digital License and activate with no issues.

The Assistive technologies Free Upgrade (Loophole) Officially ends Jan 16th 2018 too....

Windows 10 upgrade for assistive technology users