This is how it goes down.
You keep receiving letters from your ISP saying your router is not under warranty and you can cover it with a payment. Then your internet gets faulty, coming on and off, so you call your ISP and they say they are sending out an Openreach engineer. Except they don’t. What you get is some guy in an unmarked van dressed in casual clothes. They knock on your door and when you open they say, BT. But when you ask for ID they produce an ID card from another company completely different and unheard of. They say they are working for BT but actually employed by this no name company and that you should have been told, by your ISP, they and not Openreach were coming.
This guy then puts an ipad down on your table and asks for your wifi password if it is different to the one on the back of your router. When you refuse they get aggressive. They are also not tech savvy when it comes to networks so they look confused if you’ve changed the default settings on your router, more so if you mention ‘MAC filtering’ or anything like that.
They then disconnect your router completely and check the telephone line before calling an Asian sounding person to schedule an appointment for a real Openreach engineer to come out and check your system in a few days. When they leave, you will notice that the router they leave behind is not yours but has been replaced with another one. The label on the back will be different. It will have a different MAC address, possibly by only one digit. If you were to check your network you will find that your cabled connections go through the substituted MAC address. But your wifi connections will go through your old MAC address even though that router is gone with the aggressive guy.
An Openreach engineer will come and then leave saying that your system should be working now and all you need to do is wait for it to start up; except that the router will be on, idle, and show none of the flashing lights when it is starting up. Once this engineer has left you will find that you have internet with cabled connections but your wifi is dead.
And if you try to navigate to your ISP’s admin page to check your internet you will be refused even though you can surf the rest of the entire World Wide Web.
You will then be told by your ISP you need to pay for a new router to replace the one substituted by the aggressive guy because, it is faulty and not under warranty.