Thats not true that due of your overstay the visa wasnt approved, maybe thats only your new employeer PRO reason out, ask him/her maybe your previouse company file case againts to you. If ever your holding your passport, First option much better go to Al-Awer immigration paid the overstay but in that case you holding ticket going out UAE, second option go to any travel agency for exit, The travel agency already guide you. Again make sure you dont have case in immigration only the overstay.. This advice base in my experienced. My company file case againts to me absconding thats why I cant go out exit to other country. I need to remove absconding first.