This is not a BT issue. There is nothing any one on this forum can do to help you.
If you are concerned that you have been hacked and that somebody is watching you, you should report the matter to the Police.
Hubs are fairly secure out of the box. Security best practice dictates that when you get a router for the first time or a new replacement you should change the default passwords and the SSID (broadcast name). Even better is configure the router not to broadcast the wireless name (SSID).
Passwords should be as convoluted as possible, you normally only have to set them once for each wireless device. They (passwords), should contain a mixture of upper and lower case characters, numbers and special characters. Something like this example: 3&Bg6@:^M7w9f%
The longer the better.
The most likely scenario is that someone has been careless online and allowed malware to be downloaded onto their device, PC, laptop, tablet or whatever. Then this infects other devices on the network which in turn download all manner of nasty applications further contaminating everything connected to your LAN.
Once you have some malicious software on your devices it has access to stored passwords, browser history, personal information stored on the device, for example bank account details and other account log in data. Not good. The best way to be certain you have removed all malicious software is to format the drive on PC and/or laptop then do a clean install from your backup and restore mobile devices to factory defaults. Only way to really be certain. Then exercise some discretion when online in the future. The Internet can be a dangerous place for the careless user.
Finally. Never share the wireless password with anyone. If you need a guest network then buy a router that supports this and you can change the password on a regular basis without affecting your own networked devices. I have noticed quite a few routers placed on window sills with the password stickers viewable from outside. Unbelievable I know, but I have seen it happen.
Security of the home network is the responsibility of the person in charge of it, as in the broadband account holder. No one else is to blame for security breaches, certainly not the ISP.
It has nothing to do with BT or the equipment you have been supplied. It is your responsibility to make sure of your own security. Liam has given you good advice.
If you are unable to fix the issues yourself you should take all your devices to a reputable computer repair company and have them examine all your devices for malware etc and as has already been said, you should report the matter to the police if you feel that your neighbours have hacked you or are spying on you.