Not allowed to pump at work

I’m going to try my best to explain this,

I work from home. The company I work for, has a “client” company that is who I DO work for.

I’ve been working here since July. Starting tomorrow, I have training for a new position (group training) and cameras are required on at all times.

I emailed the trainer and asked if it would be ok every so often, once an hour or two, to turn my camera off for maybe twenty minutes to pump breastmilk. I assured her I wouldn’t be leaving my computer and still able to participate, and she agreed that would be fine.

I just got an email by a supervisor saying even though the trainer said it was ok, she is retracting that because the client requires us on camera at all times and I can pump on the 2 , 15minute breaks and lunch provides throughout the day.

My daughter is under orders from her doctor to feed her every hour or maximum two because of a genetic condition. This isn’t often enough for my pump schedule, as well as her eating schedule.

What can I do. I’m so upset with this job over so much and this is just icing on the cake

*update*

I asked the supervisor if a doctors note would help at all and she said no. I sent the emails to HR and was a little bitchy about it too. If they deny my request as well I’m just going to pump on camera until they allow me my privacy.