How do I cope as an only child whose Mother (82) is not demented, but living in squalor and refusing any help from anyone?

My 82 yo mom lives alone in a big apartment building with high security--a good thing, except that the only way to get into her apartment is for her to tell the front desk to let you up. She is not demented, but is in massive denial about getting older and numerous health problems. She is definitely depressed. The last time I was there was a few months ago. She fell and finally agreed to let an ambulance take her to the hospital, where she was for several weeks. I cleaned her apt during that time and was appalled. She had been ordering takeout daily and not throwing anything out. Newspapers everywhere. Roaches. And the worst is that I discovered she has been dealing with fecal incontinence, the poor thing. So I had to throw out most of her sheets and towels.

Anyway, she returned to a clean apartment and allowed her cleaning lady to come for the first few weeks, but now she's back to canceling everything--cleaning lady, dates with me, doctors appts (she was supposed to see a GI specialist for the fecal problem). Anytime I try to reason with her, she gets furious with me. She insists she needs no care, no help, is perfectly fine and it's her business if she goes to the doctor or not. I know this is true, but it's killing me. I am so afraid of having to go back to that apt whenever the next crisis hits. I actually called APS anonymously and they showed up in her lobby but she would not let the person upstairs! I am terrified my mom will find out I called them (but APS will keep it anonymous/confidential, right??)