BT WIFI extender 300 not working with my plusnet router

[#1]

When I first set up my router I could connect the BT wifi extender 300 I have. However just after PlusNet confirmed they have set up my phone line I can now no longer connect to the internet via the router, The phone line thing is probably a coincidence but nothing I do will fix it.

Does anyone have any ideas as I do not want to go the expense buying a new extender as this one should be good

[#2]

Perhaps reset the extender to factory and re- pair it to the router? Had to do the same with a friends extenders recently.

Mark