Being told my details are incorrect - can't access my account

I've been an ID customer for a few days now and I have to say, I feel like I'm running round in circles.

When I try to access my account, I'm getting a message that my details are incorrect. I've checked my username and it is correct. So it must be my password. So here's where the problems start. When I choose the incorrect password option, I'm asked for my number, last name, username and date of birth. But when I ebter these, I get a message that some of the details are incorrect. I've been trying now for 3 days and its getting to the point where I'm getting really angry about it.

Throughout my sign up period, I've had quite a few emails from ID. But none of them include a telephone number. I had to get the number by ringing my wife.. I need to get my old number transferred but its impossible at this rate. What can I do about this?