Plugin compatibility issues with Theme classipress

Hi im using this plugin with a bit of custom work to add location to my site but i’m having compatibility issues on one of the pages (payment page), It works really well with most other pages but this page cant be found when using this plugin, any chance of some help to fix this ?

its very unlikely the custom work because that only add locations taxonomy
and i have no issues on rest of the site.

If you can help im happy to share think and login details to my development site.

https://wordpress.org/plugins/custom-post-type-permalinks/