How to prevent bluetooth hacking?

Recently, my iPhone & Macbook have been getting hacked via bluetooth. Whenever I check, there is a random device that I do not recognize automatically connected to my bluetooth & there is NO option to disconnect them. All I can do is turn off my bluetooth. This is extremely troubling/worrying since I have personal information on my devices that is at risk. I'm absolutely astounded that Apple doesn't have a way to turn off "discoverability" mode or make my device invisible. More people should be worried about this, this is the world we live in now. If you use any device to connect to bluetooth or wifi, you could be at risk. Be careful!