Updated

A House committee is probing the widespread technical problems with the launch of the ObamaCare website, including the contractors that were paid hundreds of millions of dollars to create it.

The House Energy and Commerce Committee announced Thursday they have scheduled a hearing on the issue for Oct. 24, and have asked Health and Human Services Secretary Kathleen Sebelius to attend.

Committee member Rep. Leonard Lance, R-N.J., told Fox News' Greta Van Susteren Thursday night he wants Sebelius to testify at the hearing but she has not so far responded "favorably" to the proposition.

The committee, amid the dispute over the now-lifted partial government shutdown, has been steadily firing off letters over the past several days seeking answers to why the HealthCare.gov site was not fully operational when it launched on Oct. 1.

"Despite the widespread belief that the administration was not ready for the health law's October 1 launch, top officials and lead IT contractors looked us in the eye and assured us all systems were a go," Chairman Fred Upton, R-Mich., said in a written statement.

He said the technical problems have reached "epidemic proportions" and the American people "deserve to know what caused this mess."

Much of the scrutiny has focused on the company that received the bulk of the taxpayer money to help create the website -- CGI Federal, a U.S. subsidiary of Canadian firm CGI Group. According to the company's own announcement, it secured a contract in late 2011 worth a total of $93.7 million, with the base value at $55.7 million.

Reports have ranged widely over how much money has ultimately been spent on the flawed site, via CGI and other contractors. Reuters reported on Thursday that the potential total value for CGI's work has tripled, to nearly $292 million.

Upton and other Republicans on the committee recently wrote to CGI President Michael Roach questioning the company's prior claims to the committee, in advance of Oct. 1., that the implementation of the ObamaCare exchanges achieved "all" its key milestones.

"As you are aware, the rollout process ... has been problematic," they wrote, citing concerns that the problems may be due in large part to poor architecture of the website. They asked for information on how the system was tested, the analysis of the current problems, and what fixes are in order.

They also wrote to the head of Quality Software Services, Inc., another contractor involved in the launch.

According to a Government Accountability Office report in June, Qualify Software Services received about $55 million for "related activities" on the ObamaCare exchanges. All told, the GAO reports that the Centers for Medicare and Medicaid Services doled out $394 million between fiscal 2010 and March of this year to dozens of contractors to set up the health care "exchanges" and perform other related work.

Reuters reported Thursday that the CGI deal in 2011 grew out of a 2007 contract. A string of additional multi-million-dollar payments were approved this year; the company reportedly has been paid nearly $200 million to date, with the potential value of the contract reaching $292 million.

The additional work reportedly was agreed to in response to new requirements on the site.

Since the launch of the site, technical problems have prevented many would-be participants from actually enrolling. Administration officials say the operators are working "24/7" to correct the issues.

"Health care reform is more than a website," White House Press Secretary Jay Carney said Wednesday.

He said that while the site glitches are "unacceptable," so is leaving millions without health insurance.

The House Energy and Commerce Committee is also seeking enrollment figures from the Department of Health and Human Services. The administration so far has not released those figures.

A representative with CGI Group did not return a request for comment.