How will you know if the MAC Address connected to your Wi-Fi is a mobile phone or a laptop/computer?

So our neighbor asked to connect to our Wi-Fi network so they can have access to the internet. However, our 5mbps internet connection has a data cap of 60GB per month. Since desktop computers consume more data than mobile phone or smart phones, I want to know if these MAC addresses are both mobile phones or computers. I searched on the internet that they're both manufactured by Lenovo - c8:dd: c9:f0:56:4b and 74:04:2b:12:2a:78.

There's no way. Usually the device name connected will be pretty obvious.

Easy… Lenovo only makes computers (no phones)

Wrong, computers and laptops may use less data. It depend just what you are doing on each device as to how much data is used. Sometimes I watch Netflix on my phone.

If you don't want them using your network any more, hide the SSID and change the pass phrase. When your neighbour asks about it, tell them the router has broken.