This is what I have here in the States, considered 'unlimited' as far as whoever uses it but limited to only 5 devices at a time.
If you were the main account holder, you should have been able to go to your profile & sign everyone off/delete their profile and then change the password. My profile screen shows 5 profiles, myself-my daughter-2 grandkids and an open profile box. One day I just happened to notice that one of my granddaughters friend had set herself up a profile and was using my account, lol. She had seen where my granddaughter had written down the email & password and just took it upon herself to add on. I promptly went in and deleted her profile and changed the password. It is not that I cared if she used it, she just never asked permission and she is the type to give it out to everyone she knows.