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You need to add an author parameter to the query that is creating $cust_loop. You didn’t post that part of your code but something like:

$cust_loop = new WP_Query( 'author=123' );

Or:

$cust_loop = new WP_Query( 'author_name=rami' );

Note: Both of those taken (almost) straight from the Codex paged for WP_Query.