Can't reinstall Mavericks on 2010 Macbook

Hi everyone,
I'm trying to reinstall the hard drive since I'm selling my old 2010 Macbook (white unibody).
When I get to the point of reinstalling Mavericks, after I type in my Apple ID I get the message 'not available at this point' or something like that.
I've done the internet reboot (option-command-R) and I just end up where I started.
Does this have something to do with whether or not the laptop came with Mavericks? Or if I purchased it with old Apple ID?
What can I do now? Thanks for any advice!!

Mavericks is no longer available via the Mac App Store. Unless it was downloaded when it was available (under purchases). If you used a different Apple ID to download Mavericks in the past…you need to use that Apple ID to download Mavericks now.

If you have a different Apple ID now (and Mavericks was never downloaded with this Apple ID)…then as I mentioned…Mavericks is currently not available to folks who did not download it before (when it was available).

- Nick

I inherited and refurbished a "broken" white 2010 MacBook from original owner who had lost the original install disks. After many attempts to install OS X on the new hard drive, I made an appointment at an Apple Store Genius Bar. They simply flashed on the OS and since then all is fine. All subsequent updates worked fine on that machine, now running Yosemite. I had proof of ownership, etc.