1. change the name of your wireless router.
2. MAC address filter on your wireless roueter, so only your computer can use the wireless router
3. WPA password.
4. after finished step 1,2,3 , disable your wireless router from broadcasting its name, so others can not found its name to make a new connection.
Then you will be free from those trouble.

估计只有公寓会发生这种事。