Any chance to still get image retention fixed/replaced?

Hi all, I currently have a macbook pro retina display (Mid 2012) and it has the old burn in or image retention problem. I live in Bolivia, which is mainly why I haven't been able to take it to an apple store so they can take a look for all these years, I did take it to the closest certified apple service provider, which I found registered in this site (apple support), unfortunately they told me that there was nothing they could do...

So, I'll be traveling to US once again, I'll be in Houston for 10 days, and I would like to take this as a chance to finally get rid of this problem.

• How long does it take for apple to fix this problem? my guess is that a screen replacement is the only to way to fix it, since it is indeed an LG screen proved to have this issue long ago.
• How much (approx) will I need to spend?

Thanks in advanced for any help or suggestions.