Blue Shield of California is blaming a phone system “routing” error after a San Francisco firefighter’s oncologist was unable to appeal the denial of his cancer treatment claim.

Dr. Matthew Gubens, who treated veteran firefighter Ken Jones, promptly called the phone number listed on the denial letter to challenge the decision. But the appeal never got off the ground because the number routed him to a line intended for patients — not physicians — preventing the appeal from being submitted.

Jones, a 17-year San Francisco firefighter, spent his final months locked in a bitter claims battle with the insurance giant before dying from Stage IV lung cancer last month at age 71.

The insurer said the number listed on the denial letter was a “member services line” for patients, leaving Jones’ doctor to be shuffled from one representative to another.

The insurance provider was in hot water earlier this year after denying part of the cancer treatment that Jones needed to go through. While the chemotherapy was approved and covered by the insurance, it only got half of the job done.

Dr. Gubens had also prescribed immunotherapy to ensure that he was able to fight cancer with his immune system but that part of the treatment never received a green light from Blue Shield.

“Any of our cancer treatments are harder to give and less effective the weaker a patient is when we’re seeing them. Even in a disease that will lead to someone’s death, if I could get more years of quality time, that’s something patients value and their families do as well,” Dr. Gubens had previously told NBC Bay Area.

Over the months, the insurance provider continued with its explaination that Jones’ claims could not be approved because the medical guidelines do not approve the combination of chemotherapy and immunotherapy.

“I believe, wholeheartedly, that they expedited his death,” Jeanine Nicholson, the former chief of the San Francisco Fire Department, had told NBC Bay Area earlier this month. “They should be ashamed.” Nicholson and Jones had been friends for over 30 years.

At the time, Nicholson had also said that insurance companies need to be held accountable as they aren’t always prioritizing people’ conditions over their business interests.

Blue Shield is one of three companies contracted by San Francisco along with Kaiser Permanente, and Health Net. The city spends over $1 billion to insure roughly 40,000 employees and retirees have healthcare coverage.