Cannot reinstall Mac OS. All reinstall steps are not working.

I was trading in my old Macbook Pro to Apple for recycle. The steps for return say to erase the hard drive and reinstall the Mac OS.

The machine is MacBook Pro Core i5, 2.53 GHz, Mid 2010. I believe it was running Yosemite. I do not have any disks for the machine. I was getting errors because my browsers were out of date, but to update them it wanted me to update my OS. When I went to the app store to upgrade to OS, it said my computer could not upgrade. So I decided to give it up for Apple credit.

So I followed the steps to erase the hard drive and that seemed to go fine. Then I went to reinstall the OS and the machine restarted. I immediately did a command R upon start up. It goes into Internet Startup recovery. On wifi, I select my network and enter my password and the globe spins for a bit, then I get -2100F.

So then I do a restart with it plugged into a ethernet. It will give me the spinning globe for a while and then it will tell me it cannot install the OS because the "installer resources were not found" and I need to restart. It looks like it is trying to install High Sierra.

If I restart and hold down option key, my HD is not available. I get an external drive that is not even plugged into the machine.

If I restart and hold down shift+option+command R, I get the Apple logo with a progress bar, then I get "macOS could not be installed on your computer".

If I click the message window, I get access to the menu bar where I can access Disk Utility and Terminal. I cannot access any other options in the Utilities menu.

Under Disk Utility my view shows my HD and then it has Disk Images and shows OS X Base System. It 2 GB on it but I can't do anything with it.

I also created a bootable USB drive with Yosemite on it from my PC (I don't have a second Mac) and used TransMac to format for Mac and create the bootable disk. I plug in my USB, start up while holding Option key. I get two options: macOS Installer and OS X Base System. The macOS Installer has an arrow under it so I select that one. I get the Apple logo and progress bar. After about 10 minutes, I get "macOS could not be installed on your computer".

I have tried all steps in support and online that I found to reinstall the OS and none of it is working and I cannot get to the Utilities screen to use my Time machine backup to reinstall.

I cannot return for credit now because it's considered "damaged" yet it was functining fine (other than browsers out of date) before I did the erase of the HD.

What should I do next?