Pumping at work question

I returned to work about 3 weeks ago. I work at the reception in a hotel. Is not a very big hotel, we usually have max 2 people working at the desk.

Since I’m a breastfeeding mom I requested prior to my return to work 2 pump breaks, 25 minutes each, 3 hours apart. When I mentioned this my uneducated management did not wanted to comply with it. I literally had to hint that by law I have the right to do so. So they do agree with it.

I really haven’t had any issues with it until this week. I had 2 days working completely by myself, no coworkers in my department no management of any kind. Which I think is very unfair.

To be able to have my pump breaks, I decided to ask one of the housekeepers, as a favor, to stand at the front desk and tell guests to wait until I was done. I felt terrible, because guests shouldn’t be affected by it. I do care a lot about my job, but my son comes first and if I have to leave the reception alone I will.

I don’t think I should be the one in charge of getting my breaks covered by an employee, I think management should schedule this. I’m a wrong? What should I do? Should I open a case?