I have a macbook, 13 inch, last generation. I must use an ethernet cable to connect to the internet in my dorm room, and I find that it won't "hook" into the ethernet slot. It fits into the slot just fine and I can connect to the internet, but the cable doesn't "hook" in and can easily slide out. I've tried numerous generic ethernet cables to no avail. Is there any Mac brand ethernet cable I can use or is it just some random defect on my laptop?