Leah, Just follow the HELP center of the website

At first you need to log in to aliexpress and review the shipment status (http://activities.aliexpress.com/adcms/help-aliexpress-com/track_package...)

IF there is a considerable delay, you can make a refund request and escalate it further.
http://activities.aliexpress.com/adcms/help-aliexpress-com/make_refund_r...