csv export fails, correct tmp dir

hi there
I still have the same problem with csv export “Unable to write to temporary directory /var/lib/mysql-files/”

I changed the tmp dir correctly, I even use:

if ( defined( ‘WP_TEMP_DIR’ ) ) {
return trailingslashit( WP_TEMP_DIR );
}

and it returns the correct path “/myhome/myaccount/public_html/wp-content/tmp/”

notice that we can′t change some setting because we are using shared hosting

Thanks for reading