Issues with a supervisor

On this placement, first the first time this year, I have had a few issues with my supervisor (i.e. facility not tutor). I feel like my job there is to pick up their extra clients and to make their schedule easier rather than to learn, whilst I want to get extra experience and find out about all the different aspects of working at the centre I don’t want to miss out on other opportunities (and my lunch break) in order to help them out. I simply don’t have time to do all of the things I am being asked to do.
I have been doing playgroup, hydro, home visits (both with my supervisor and sometimes on my own), getting quotes for equipment, ringing parents to organize appointments and sometimes schools (once because a school wouldn’t respond to my supervisor so she got me to try instead), writing up and updating detailed ICF’s (impairment-activity limitation-participation restriction tables) for every client and writing progress notes for each client I saw on my own, going to different clinics, writing treatment plans and liasing with other staff, and (excepting playgroup and hydro) most of that was today!
They also don’t act very professionally in front of me sometimes and they don’t always seem to have the right attitude to working with families, such as this week when they called the mother of one of our clients some very rude words whilst discussing their case with another staff member, and acted like the person was going out of their way just to annoy them. I was treating that client (on my own) and knew exactly who they were speaking about, and whilst I can understand why they said it, I absolutely don’t think it was appropriate to say it in front of me.
Also, a few weeks ago, I had my phone with me in my bag (not on silent-because I needed to leave it on in case my supervisor had to call me whilst I was out and about on home visits), and I was talking with my supervisor in their office (early in the morning before my official start time) and my phone rang, I answered it because it was home calling and I thought it might be important. I apologized profusely (as it would normally never happen as a) I would usually have it on silence and not have it with me on prac and b) I wouldn’t normally answer it). They didn’t say anything at the time. The next day they told me it was really unprofessional to have it not on silent, especially when on home visits (when it is ALWAYS on silent) and that they really didn’t want to have to fail me because of it so make sure it never happens again. I immediately put my phone on silent and later that afternoon I drove all the way out to Armadale (in one of the centre’s cars-50km out of my way) because I missed my supervisors call to tell me that that client had cancelled, because my phone was on silent.
I have spoken to them about some of this and sorted it out, and in future I will always talk to my supervisor straight away to clarify any issues, because I waited a while to sort it out on this prac and I was getting really stressed. I will also speak up about the limits of my time and my need to have some free time, and time to learn (i.e. experience different aspects of the services available and how they work). Generally they reacted quite positively and explained why they were asking me to do those things and changed my schedule where needed to allow me to participate in the AFO clinic and do some appointments at PMH. I haven’t spoken to them about the issue of talking about clients in a derogatory manner because I am not sure how to broach the subject or how to deal with it, I am going to speak to my tutor about it but am not sure what else to do, any ideas anyone? Cos I feel like I'm whingeing and whining about this stuff (sorry for the long post) but I think it's an important issue.