Very stressful, poor management, cut throat culture.
When I was there (until 2014) they had implemented multiple shifts, too often there were not enough seats, you could never expect to sit at your usual seat. Days with overtime were the worse, many times computers didn't not work.
Mandatory shift change every year, if you worked days, you might be given a night shift, this included getting a new immediate supervisor, who usually had an entirely different way of doing things.
At first there were tests every 3-4 months, when I left; tests were given every month. The company does not want a union, employees were told not to speak to any Union Rep,, several years ago the former head of call center threatened that if a union was brought in she would close the center.