EX2700 i cant remember login or security answers

ive got a new internet recently so ive had to reconnect my extender and it is asking me to login, i cant remember the username let alone the password so i clicked username and password help and its security question, sisters name and best friends name, im definitely not getting those questions wrong but it says i am and often times it just comes up with timestamp has expired please return to menu, any ideas how i get round all this?