AVIS disappointment

I was totally disappointed with the entire service: Firstly when I called to make my booking I was quoted a lesser amount and if they play back the recording they will hear that I distinctly double checked that the amount included all insurances and super cover etc etc. Secondly, I waited for a long while in the queue at the airport and there were all of 2 people at the counter for a very, very long time with queries, then other people skipped the queue - not sure if they were privileged members or..... Thirdly, at the counter, I was told that the amount was different from what was quoted to me... Fourthly, when I took delivery of the vehicle and was just outside the airport I got a strange call from the what they said was from the tracking company - Discovery and that the BMW which I was driving had sent out a panic tracker - I told the woman that I was not driving a BMW, she then asked me who I was so I in return told her she should have all my details on the system if she called me, and she said she didn't (this conversation was recorded as well) Upon my return home, I called or attempted to call the airport and the phone just rang on a constant basis, after a long, long while I was put through from the roadside assistance (very kind lady) who made sure that I eventually did connect with the airport. They took my concern, said they would investigate and get back to me. I told them that I told the lady that she should have had all my details on the system and the Avis guy that attended to this query agreed - I'm still waiting to hear what this was about..... Finally, I returned my car only to be told by the Avis guys that received cars, to leave the keys in the car that they were busy and will finally get to it when they are done. I left with my husband being the witness that the keys were in the car upon delivery. I rented many vehicles from Avisany vehicles through my company Unizulu and have never had this been a problem nor been treated in this shabby manner. I then received my invoice and upon querying the amount of over R800 for a one-day rental, I was told that they would get back to me. Nobody did and I am still awaiting feedback with regards to all my queries as well as my bill. In the meantime, I have been charged with nothing being resolved.