My boss had promised me part time going back to work since that schedule became available while I…

My boss had promised me part time going back to work since that schedule became available while I was gone; & he told me to call him 2 weeks before i went back to make sure... & sure enough he bullshitted me. Im still fulltime. My job goes by seniority & ive been there 4 years, & he said part time isnt available but it isnt fair cause girls that have been there for 6 months or less have the schedule i wanted. 😡😡 my boyfriend works where i work & he had already picked an opposite schedule of mine to watch baby. & now we have the same schedule. & need to pay a sitter. . . Super pissed!