The interview process is quite simple: you take some tests and if you do not pass, you are sent home. The test is designed for college students and by using it, they aim to weed out professionals with experience -- because they will have to pay them more. I recommend telling the girl at the desk that you were told you would have an interview. Ask specifically to see a recruiter. If she doesn't let you, request her manager. As long as you get to the interview, the rest of the process is not difficult. I think they like to see that you are persistent. The "won't take no for an answer" is a huge part of the culture at the company. Just because you can't do algebra, doesn't mean you don't deserve an interview -- let them see that determined side of you and they should look past your test scores.