Yes, the utility company can disconnect your service if you do not pay for it; the fact that you need oxygen does not obligate the utility company to provide you power or electricity for free. You can probably go to court and get a court order delaying the disconnectiion, to give you  time to make other arrangements; you may also be able to qualify for various forms of aid or subsidy, such as potentially from the utility company itself. But ultimately, if you do not pay for the service, you will be disconnected. You should speak with an attorney about this immediately; the lawyer can both get you extra time (whether by negotiating with the utility company or by seeking a court order) and also help you locate any resources for which you qualify. Good luck.