Remove code from system for deleted listing

I deleted a listing for a PSN gift card code because I didn’t want too many listings at once and now it’s stuck in the system. I get the error “code for digital goods already exists” when trying to list it with auto-delivery. I know I can send the code as a comment if it sells but it seems nobody is interested in buying it that way. Can the code be removed from the system so I can list it with auto-delivery?

Nevermind. It sold. I won’t make that mistake again.

Now the buyer is saying it’s not working. It’s saying it’s already been used. Would it show as used if it’s locked into the Gameflip website? Would have been nice to avoid this if the system didn’t lock codes in if listings are deleted.