Store manager met with me and we sat in the breakroom; very friendly and informal. It had the feel of a real conversation - very organic - but there were sticking themes and lines of questioning naturally. A prominent feature in the interview is to ascertain how much the applicant knows about T-Mobile. There were several questions meant to probe my projected longevity at the company. I would recommend asking questions about upward mobility and similar positions to imply that you are considering remaining at and contributing to T-Mobile beyond the position you are applying for.
Even though that position did not involve providing customer service, the store manager was emphatic that good communication skills were necessary for that position, so be prepared to provide an example of your great communication skills!
Of course, there was the usual questions about strong task management and asking for examples of your success in this area at your former workplaces.