It was great as a student, then a bad manager ruined it for me, and upper management did not listen to complaints - Sales Assistant O2 Employee Review

All was going well, then a bad manager joined and ruined it for me, forcing me to work during class times that were pre-agreed and being toxic to me in front of customers. I complained to upper management but they never listened or replied to my complaints, after enduring a few months I quit for my mental wellbeing