Not getting paid for my RN work

I need some advice. I work now for hourly wage for a hospice. I will be on salary at the end of my 90 days probation period. Well, when you are on call all you get is a $50 beeper fee for being on duty for 15 hours. During that time, you may or may not get called out to a patient, or you may have to answer the phone and deal with a problem for a patient/family member/caregiver. This is after working 8 hours during the day. But, then all you get is the $50 beeper pay. No other pay. Not even your hourly pay. The company says they have always done it this way. If I were already on salary I would think "Ok, that is at least some kind of pay". But, I am on hourly pay. I think I should be paid hourly pay because I at the on call status, you are in charge of all the patients and their needs. Whether you get a call, or go out on a call or not. You are still "on call". On duty. What do you think? Please tell me what you would think if it were you. Most of the nurses have had this happen through the years. I personally think it is a rip off and a nurse "on duty" should be paid. Even if she doen't get a call or go out at all all night. Just because she is "on call".