ZIP code redirecting incorrectly

Hello my website is http://www.crystalairsystem.com we are having issues with this plug in. The information they are inputting in the woocommerce checkout is not being redirected correctly to 2checkout. On the 2checkout page intead of it showing the ZIp code #### its showing the filling the country as US, only when choosing billing address is different to shiping address zip code shows on the below page. Please help. Thanks in advance.

https://ww.wp.xz.cn/plugins/woocommerce-2checkout-payment/