3 Interviews:
Phone interview with recruiter.
This one should be the easiest one. Usually all recruiters are very nice and they want you to be successful. But, it is mostly an interview where they will ask you about your past experience, why you left your others jobs, why you want to work in a customer service position, and most importantly, why Ultimate Software.
Panel interview with high up managers.
From the moment you walk in, they are already screening you. How you introduce yourself, talk, walk, etc. They say that within the first 2 minutes, they'll know wether you're a good fit or not. So, make sure you bring your A game for the first 2 minutes!
This one is similar to the first one, but they'll throw in some behavioral questions. "Tell me about a time where you had a tough situation with a client and how did you solve it?"
If you do good on this one ( DON'T BE NERVOUS ) you will take a quick test.. You should be fine as long as you use common sense and bring your analytical skills into play.
Panel interview with future managers from teams.
If you're here, you should be almost good to go. Previous managers think you're a good fit and want to run you through potential team managers. Don't be nervous for this one as you almost made it, but, it can and will break you if you think you've got the position already.
Mostly behavioral as well, with questions about your previous positions. Be confident and enthusiastic. I mean, this is Ultimate Software, if you aren't happy you made it this far, then you should look elsewhere.