Working Mom 母乳 time not paid -- not protected by law?

Please help:
I used to go home and 母乳 my baby 40 minutes to 1 hour every day when I work at full time. My manager just told me that HR said it is not covered by working hours, so I need to work extra hours in order to meet 8 hours requirements. Does everyone know this? I thought it is protected by law, and we have a room in the company for pump, but I choose to 母乳 directly at home.
I was also told lunch time (1 hour) should not be counted as working hours even if you just finish your lunch within 20 minutes, so the total time in office has to be 9 hours and if I 母乳 my baby, I need to be in office like 10 hours, is it true?
Too sad...
Thanks!