Undetected for 5 years!

Mom was recently diagnosed 2 weeks ago with melanoma to the liver. She had a Choroidal melanoma 5 years ago and had to have her eye removed along with the melanoma. For 5 years she has went faithfully to her oncologist getting excellent reports back each and every time. 3 weeks ago she started feeling ill and had some swelling under her rib cage on the right side. She went to her family doctor and he took and xray of her abdomen and said that her liver was enlarged but they would call it stomach flu for now and take some blood tests. I went with her to get the results 3 days later and her liver enzymes were elevated. We were referred to a gastroenterologist who did a basic physical exam and he said that her liver was twice its normal size. She was already turning yellow. She was admitted that evening to the hospital because I called her oncologist, we sat in the ER for 6 hours before we got a room. She is now vomitting and in real bad pain. Her oncologist wasnt on call so we had to be seen by her associate whom we had never met. On the 4th day after them drawing almost more blood than she had the gastro doc did a liver biopsy. We were sent home the next day with all kinds of meds to keep her from being nauseated and keep her bowels moving, we were told to see her oncologist in 3 days, but that they didnt think it was cancer. We arrived at the oncologist office at a 415 appointment, she now is weak ,literally glowing from jaundice and fighting back the pain and nausea and we got in to see the doc 2 and half hours later. I also notice that now her feet and ankles are swollen! The doc comes in tells me and my stepdad to sit down and she tells us that mom has stage 4 melanoma to the liver. She wants a mri of the brain and a petscan to see if its went anywhere else and then she will have her insurance person get on the phone with moms insurance person to see what treatment will be covered,and to setup the 2 tests, BUT, its Thursday and that person wont be in until Monday! I cant believe my ears, Im still choking down the news of the cancer. As I type this tonight, we are just now being able to have the MRI/Brain tomorrow, the petscan 3 days later and we cant get in to see the oncologist until the 31st! Im so angry and lost and my mom still wants to keep going to her oncologist because she has been seeing her for 5 years and she doesnt blame anyone for whats happened. I just want someone to do something and stop dragging their feet. Cancer doesnt stop for weekends or appointments!