Is it legal to refuse servers tray stands?

I have been a waitress for X company for over a decade, and since we're one of those diner/Denny's type of establishment, we have never before done tray service. Our owners recently decided they wished to make us look more like a fine dining establishment and therefore are now requiring and forcing us to use large trays to take food out to guests.

The problems are that

A) we don't have stands to place these trays on and they refuse to bring them in for us

B) the majority of the staff have never been trained in using these large trays

C) said trays get very heavy, are an awkward size, and can't even hold the plates correctly because the dishes are oval shaped and large

D) when explaining that our writs/backs are hurting as a result of this usage we are told to "use them or we'll be fired"

Is what they're doing legal? Our company is based out of, and mainly in California, with a few locations in local states, but we're not national.

So is there any law in California requiring stands or protecting servers? I also feel like being told to do this or lose my job is very stressful. We even have a regional manager who stalks the restaurant by parking outside and watching through the large windows we have to make sure we do things as they wish.

Is there anything we can do? I'm afraid to e-mail or call human resources for fear of retaliation. As it is, I have lost hours for refusing to work days they wished me to. I feel as if I do contact HR they will pay me back in some way.

I am not the only employee who feels threatened, stressed, and overall fed up. There are many who are hurting from these new policies and rules but don't know what to do or if we have any legal rights or protection. After asking around, I have found that most of the employees are fed up and barely keeping it together. One girl almost walked out a few days ago because of the stress and the pressure. She is a very capable server, very level-headed in general, and not the type to cause drama or create scenes. If she was that upset she would have had good reason. Any help or tips would be greatly appreciated.