log a complain on their website,
clearly stating the date of purchase, model no, store location, the details of the rude behaviour and your contact details.
they dont have an exclusive website for MENA but you can go on their international site and log you complain,
www.sunglasshut.com
they take the complains very seriously.
you can also visit their facebook page and leave a post.
atleat the guy will be reprimanded and will not repeat with other coustomers.