macOS recovery won't reinstall high Sierra because it's still Beta

(I realized I posted this in the wrong discussion! Now I am in the correct one.)

Hi all, I'm having an issue with my early 2015 MacBook Pro with Retina. I upgraded and got a new laptop and went to wipe everything off the old one. Well I did, and when I went to reinstall a macOS all it could find is the Beta that was last installed. I picked it and after like 40 minutes it gave me some error. I tried to boot it up to the os that it came with but it keeps showing the Beta. I opted out of the beta before I wiped it but, obviously, it was still installed. How can I fix this without having to pay geek squad for a brand new os? Thank you!