Worst service ever from a big company

Good afternoon, I have an account with the oxygen air product company where they gave me the home oxygen machine, on the 10th May the machine was not working, I phone the company to explain the situation the guy on the side his name Deon said they dnt have the drivers at the time wich was around six in the morning, and he told me he can only sent someone during the day, and I told him it can't be during the day cause my wife rely on that machine, and now he changed the story and said if I want someone to come immediately they going to charge me R400, wich I said I will not pay cause my understanding is their company is 24hours,i had to tell him that if anything can happen to my wife I am going to sue their company, once I said that he said he ll sent the driver wich was at the house within an hour, but the problem dnt stop there 5 days after they dropped the other machine it also stopped working, I had to call their company for almost two hours cause the number was only ringing, and I decided to call one of their drivers cause I have his number, and he told me that he's not at work I mst call the office, I explained my situation to him and he told me that he can't help me, I begged him to give me one number of the driver that is at work but he declined, after we managed to get someone from the office I was told that they can only deliver the other machine after four in the afternoon, so for Saturday my wife has to b without the oxygen that she mst use for 24hiurs because of this company who dnt care for their customers, this is the baddest service someone can get from a big company like them