My USB port is apparently to small?

I have went and looked for mouse USBs and I have found and tested about 5 different USB males. I realized the prominent problem was the metal casing around the surface USB entry point, or the USB port was the EXACT same size as the males. So they wouldn't fit each other. It's not the mouses USBs fault because they work on my Desktop. Is there a mini USB I need to buy only for the surface? Please help :)