connection droped

[#1]

Before the weekend my connection dropped on a number of occasions, then on Saturday it went off completly.
I logged a fault , I then borrowed a Plusnet fibre router from my daughter (same as mine TG582n)
I was then able to connect with no problem, I have been asked to enter my user name and password in place of my daughters.
All my efforts to change them have not been sucessful I wonder if I am not doing something correctly ? 
This is the reply to my fault    Description: Advised to update his borrowed router with his own details.
If he can connect, the original router must be faulty, otherwise it's an account auth issue

[#2]

Are you putting your full connection username in the router? This will be in the format of username@plusdsl.net

[#3]

Yes  to the best of my abilty ,I am not100 % sure of where on login interface I should make the change.
I did it or rather tried to change following  >Gateway  >Info >Set up
If this not correct  where should I try to change

[#4]

I have checked via live chat that what Im doing login wise is correct.
However whilst I can connect to the net with the "borrowed" router it shows daughters user name.
I guess I will advised via faults if the router is faulty or if it is another issue.