Line Problem [Fibre]

[#1]

Good afternoon,
I have been having some serious issues with my fibre line which is causing disconnects and long periods of down time.
I have recently creating a Ticket via the Faults department, to which they have tested my line and noticed long periods of disconnects etc.
The problem I am having is that I BT engineer was out during the week and refitted everything in my house (Even tho there was no problem there) and has given is results.
Now tho the Faults team are sending out ANOTHER engineer to investigate the issue. I KNOW the fault is in my Router/Modem and have told the team that I will buy my own HIGH end Router,
but they are insisting that I pay the £50 charge.
Can you give me any insight into this as Live Chat is just filled with Sales people.
Question ID: 106876062
Username Devliano

Thanks

[#2]

Aside from yesterday it looks stable from here.

What happens when your connection drops? Do you get a particular error?

[#3]

Yes I get;
Connectivity to Gateway Problems
Concentrator not Reachable
My connection has dropped several times and has not been online for 11 days.

[#4]

If it's still ongoing I'd recommend raising a fault using the link below.
https://faults.plus.net