CLEVELAND (CBS News) -- A Cleveland-area fertility clinic is denying legal liability after a freezer malfunction destroyed more than 4,000 eggs and embryos earlier this year. Dozens of families are suing University Hospitals, which previously apologized, for alleged negligence. In court documents made public this week, the company said clients knew about the risks involved.

Since the incident, University Hospitals said it's taken significant steps since the incident to enhance operations and equipment at its fertility center, including increased staffing and additional training. Still, for some patients, the changes come too late, reports CBS News' Tara Narula. 

Sierra Mathews was just 19 years old when she decided to freeze her eggs at University Hospitals.  It was 2014 and she had been diagnosed with ovarian cancer.

"At the time, I wasn't really thinking about kids and I wasn't trying to have kid, so it just gave me hope," Mathews said. 

But she was one of hundreds of women who found out in March her eggs were destroyed when a cryopreservation system malfunctioned.

"It felt like I had to go back to a really traumatizing time in my life when I really felt like I was alone because there was really no one my age going through something like that," Mathews said.

Following the incident, University Hospitals CEO Tom Zenty released a video statement. In it he said, "I can't say it any more plainly. We failed our fertility clinic patients. We are sorry. I am sorry."

This week, in response to a lawsuit, University Hospitals said women and families signed consent forms, writing in court documents: "Plaintiffs were fully advised of the material risks, benefits and alternatives available for treatment and thereafter voluntarily assumed and consented to those risks."

Tom Merriman represents more than 200 clients, including Sierra Mathews, who lost their eggs or embryos at the clinic.

"You can't have it both ways. You can't go on national TV and tell the world that you're sorry and that you're taking responsibility then send an army of lawyers into a courtroom when people aren't paying attention and file answers where you deny all responsibility," Merriman said.

In a statement, the hospital said it "filed its formal answers to the complaints, as required by court rules" and "our fertility center patients trusted us for their care and we know we need to regain their trust."

"It's something very tragic and heartbreaking that we are all going through," Mathews said. "So I just think it's important for me to use my voice to stand up for the people who either can't or just don't have the heart to yet."

University Hospital said it's working to help affected patients in a number of ways including completing additional IVF cycles at no cost when possible and reimbursing storage fees.