Employee benefits in California?

I just passed probation a week ago. The employee benefits for this pet hospital I worked at in San Francisco is free pet exams and discounts on veterinary products after passing probation. Right after probation, I took all three of my pets in for exams and got some products from the pet hospital at the employee discount rate. However, my supervisor didn't allow me to pay for my bills until she reviews everything in my invoice. One week after I took my pets in the hospital for exams, I heard back from a job that I applied five months before. I wrote up an resignation letter and submitted it to my supervisor and gave them a two week notice. My supervisor then said to me that they are very upset that I used the employee benefits and is quitting right after. They said they might not be able to discount me for anything in my invoice and that I might need to pay for everything in the full amount.

My question is... Right after probation, doesn't it mean I can enjoy the employee benefits doesn't matter if I'm submitting a 2 week notice or not? Even if I do submit a two week notice, shouldn't I be able to use the employee benefits for everything before I gave that two week notice since technically I was still an employee. i was actually done with probation two week ago but my supervisor didn't said anything and pretended I wasn't done until I asked her so I wasn't able to use any benefits.

Is there any California laws on benefits that I can use to tell my employer that I do have the rights to obtain my benefits after probation so I can talk back to them? Thanks a lot