SAN DIEGO -- Protesters staged a rally against high costs and poor care outside a San Diego health insurance company Tuesday.

The group of protesters picketing at a local Blue Cross office cried out for thousands of Californians whose voices they said go unheard.

The California Nurses Association said the state's five largest health insurers rejected 31.2 million claims for health care between 2002 and June 2009 -- or one out of every five claims.

"Do doctors deny care based on this?" asked 10News' Mitch Blacher.

"I would hope not," said Dr. Ted Mazer.

Insurance companies denying care means one thing for doctors like Mazer: he doesn't get paid.

"When I basically have to pay out of pocket to see each one of those patients, you can only do so much of your practice that way before you go under," said Mazer.

The California Department of Managed Health Care responded to what the 10News I-Team found, and said, "It's important to point out that a denied claim means that the patient received the medically necessary services, but the doctor or the hospital was not paid for that care. The department has been very active in ensuring that providers of care should be paid fairly and on time."

But for Mazer and doctors in his situation, while denying care may not be an issue, getting reimbursed for it is.

"We are constantly struggling to get paid for things we know are medically necessary," said Mazer.

On Tuesday, Mazer's staff spent the morning trying to get reimbursed by insurance companies. Mazer told 10News he estimated his office spends $70,000 in a given year just trying to collect what they are owed.

Protesters said Tuesday's rally was about more than doctors getting paid. Several of the protesters have terminal conditions that they have been denied health coverage on.

Experts said if doctors do not get reimbursed by health care companies they will stop working with that health care company. Experts said that leaves patients with fewer doctors to choose from.