Here is how you can blocklist WiFi users on your network. To do so you can use the access control feature and block the WiFi user on your network. You need to turn on Access Control for this and here is how you do that.

TP-Link

1. Open your browser and go to 192.168.0.1 or 192.168.1.1.
2. Login with your default username and password.
3. Now go to Advance > Security > Access Control.
4. Under Online Devices you have a list of who is accessing your WiFi.
5. Click on the Block Icon and click save.

D-Link

1. Open your default gateway IP on your browser – 192.168.0.1 or 192.168.1.1.
2. Login using the default admin details (admin/admin)
3. Go to Wireless > Advanced Wireless > click ACL Setup.
4. Now click on “Enable Wireless Access Control Mode” and select MAC Addresses you want to give permission to.
5. Save changes by clicking Apply.

Note: Under “Active Client Table” you can see your device’s IP in order to prevent getting it blocked.

NetGear

1. Use any of the preferred browsers from your device while you are connected to the router.
2. Now go to https://www.routerlogin.net or https://www.routerlogin.com.
3. Now enter the username and password to log in with your router. The username and password by default are admin and password that you can try if they are not manually changed in the past.
4. Go to Advanced > Advanced Setup > Wireless Settings.
5. Now click on the “Set Up Access List” button.
6. In the next page click “Add” and select the Device Name from Available Wireless Cards and click Apply.
7. Now Turn Access Control On and Apply Changes.

Now your WiFi can only be accessed by the IP Addresses you’ve selected and restrict login from any other devices/IP.