The problem is this pattern will match only/pay2see/, not /pay2see/some-path or /pay2see/some-path/more-path. If you want to match “pay2see” plus any paths underneath it, then you’ll have to write it like this:
Also, it matters where the htaccess file lives. All these patterns will work only if the htaccess file is inside “ebookshop”. If, instead, your htaccess file lives at the root, then you’ll have to include “ebookshop” in the pattern.
Actually the problem is still the same that I mentioned before. You’re matching exactly /pay2see/ and not allowing for anything to come after in the URL.