LUNO BITCOIN

I invested in Luno Bitcoin and have lost my Authentication F2 Number. there is no way to contact Luno??? Keeps on taking you back to where you began. VERY FRUSTATING!! I sent them a reference number then they send you a link to a help line which once again takes you back to the beginning. PLEASE HELP!! I am not able to even view my account without this autentication number. It also keeps on saying that a 4 DIGIT CODE HAS BEEN SENT TO YOUR EMAIL - but nothing!!