Troubleshoot 2 small PHP pages

The back-end of a coupon website uses a custom PHP page to place PDF coupons onto the correct pages of the website by location and business type and mark them with expirations. The coding for this sorting is provided by the graphic designer in each PDF’s filename.

After years of use, we are suddenly experiencing two issues that I’d like you to fix:

1) Some of the uploaded files are NOT getting processed. It seems the script is iterating alphabetically and ignoring filenames S-Z.

2) Upon clicking the PHP sorting button in the web interface, the page should redirect to a new page with additional buttons. This page has stopped loading despite that the URL looks correct. I can that the PHP is still on server but, upon inspection, I can’t find anything in the code that would explain why it’s not loading.

I can first send you the two PHP pages (as well as one of the functional ones) to look at and troubleshoot. If necessary, I could grant FTP and/or cPanel access (but I’d prefer to avoid this). Thanks!