Mammograms can save lives, but CBS News has learned in some cases, insurance companies are refusing to cover them – even for breast cancer survivors. We first looked into this in October for our series, Medical Price Roulette, a collaboration with Clear Health Costs. After that story aired, we heard from hundreds of women who told us they could not afford the follow-up tests their doctors had ordered, like additional mammograms, ultrasounds and MRIs.

Roseanne Neill fought breast cancer and won. But the 52-year-old single mom said for the past year, she's been fighting her insurance company – and losing.
 
"I felt that I was being penalized for having breast cancer," Neill told CBS News correspondent Anna Werner. 
 
The cancer occurred in 2015. Since then, she's had annual diagnostic mammograms, paid for by her insurance. Then last year she switched jobs. In October she went in for a mammogram and got a bill for over $900 about a month later. Her insurance company, Aetna, had refused to pay.
 
"They said, 'No. We don't cover diagnostic mammograms.' I said, 'But I had breast cancer. Why wouldn't you cover this if I had breast cancer?'" Neill recounted.
 
The Affordable Care Act requires insurance companies to pay for regular screening mammograms for women with no out-of-pocket costs. But because she's a breast cancer survivor, Neill said her doctor told her she needed what's called a diagnostic mammogram – a similar test that's read more quickly – every year for five years after her cancer treatment. 

So Neill appealed to Aetna. She said she told the company, "I do not feel it is fair to be penalized for having had breast cancer."

"And again, when I told them verbally, there was no response. 'We're just not going to pay this.' So there was no negotiation. There was no discussion. There was no argument. It was, 'This is the way it is. Have a nice day,'" Neill said.

In a letter, Aetna told Neill her claim was "processed correctly" and that "Aetna does not consider the specific test…as part of the standard routine testing." Neill said the letter made her feel "very angry."

"I feel that it's very unfair that someone who has had breast cancer, who is following the protocol that the doctor is prescribing is not being covered for preventive maintenance, really," she said.
 
Neill is one of hundreds of women who have shared their stories with CBS News. One wrote she feels "punished for being a survivor" because of the "astronomical" costs. Another said she skipped her mammogram this year, saying "I cannot afford to have this happen again."
  
Molly Guthrie is with the Susan G. Komen Foundation, which is pushing lawmakers to get all breast cancer screening tests covered. She said this issue is "creating a significant barrier to care."
 
"We want the diagnostic testing that a physician feels their patient should have, that the patient can have access to that without cost sharing," Guthrie said.
 
"Without any cost to the patient? So that means diagnostic mammogram, ultrasound, MRI? Any of those?" Werner asked.

"Right," Guthrie responded.

So far, bills have passed in five states.
 
Congresswoman Debbie Dingell is co-sponsoring federal legislation in the House, but so far, there are no Senate sponsors. 
 
"We need to make sure that every woman has access to the tests she needs, to know if she's got breast cancer," Dingell said.
 
As for Neill's bill? After CBS News contacted Aetna to ask about her case, it reversed course, saying, "We mistakenly did not apply the appropriate policy when Ms. Neill appealed. We apologize for this mistake."
 
Neill said she doesn't believe it.
 
"It's all about money. The bottom line," Neill said.

Aetna told us it will reprocess Neill's claim and reimburse her for any out-of-pocket costs. We asked whether any other women were affected by that mistake but were told no, that Aetna believes this is "an isolated issue."

But if you have a story to tell us about Aetna, mammograms or other medical prices, visit CBSNews.com/healthcosts. You can also email us at healthcosts@cbsnews.com.