You can use any router you want, but need to know certain things about connection, as well as usernames and passwords, these are NOT your user names and pass words, they are BT ones assigned to you and pre installed in your router, see if you can access them first from the router, if not phone BT for them.
I have just last week swapped from using the plusnet supplied pile of crap router THOMSON was the make, always cutting out etc, new one has not missed a beat and is SO much faster, I now use a TP LINK TD- WD8910G.
I now know about the above as I had a to call a man out, it cost me £60 for 20 minutes of his time/work!!
tabetha