It's been seven weeks since Frontier completed a purchase of Verizon's fiber and copper networks in California, Florida, and Texas, and the company is finally explaining why so many former Verizon customers have been hit by service outages.

Bad data from Verizon is the culprit, Frontier West Region President Melinda White told lawmakers in California yesterday during a nearly-two-hour hearing held by the State Assembly's Utilities & Commerce Committee. Corrupted data prevented Frontier's network from communicating properly with equipment at customers' homes, making it impossible to provision service to everyone, she said.

Frontier is providing bill credits to customers who lost service.

Frontier has figured out how to fix the problem, but it will take another 10 days to clear a backlog of customers still waiting to get their problems resolved, she said. After that, Frontier can move into a business-as-usual mode, she said.

"If we can get the provisioning to the ONT [the optical network terminals at customers' homes] in the proper manner then all the services come back up," White said. But in a lot of cases, a customer needs to reboot equipment to get it working even after the data problem is resolved on Frontier's end, she said. That's one reason there's still a backlog of customers without service.

Lawmakers will likely continue to keep track of Frontier's progress. Though White seemed certain about the 10-day timeline, Frontier previously said it would fix its problems by mid-April. Frontier has also faced pressure from Florida Attorney General Pam Bondi.

White did not explain why the corrupt data didn't cause problems for Verizon customers before the wireline networks were sold to Frontier. We contacted both Verizon and Frontier for more details today but haven't heard back yet.

Frontier says that less than 1 percent of customers who were switched from Verizon to Frontier suffered service outages after the transition. That could put the number of customer outages at around 30,000. It's not clear how many customers still lack service. White said there are still more than 200 customers in California who lack VoIP phone service, but outages also affected Internet and TV.

Explaining the data transfers, White said Frontier imported more than 440 million "data extracts" from Verizon in the three states, and some of it wasn't correct. There is a broad range of data types, including phone numbers, addresses, serial numbers on network terminals, and more. It includes "anything that has to do with bringing over who is a customer and what is required in order for their service to work," White said.

Frontier's back-end systems must connect to equipment in customers' homes to establish that they've been switched to the Frontier network and to provision all the services each customer pays for. When data is incorrect, that process goes haywire.

Separately, some customers still don't have access to all the on-demand video they're entitled to. Frontier needs until mid-June to fix that problem, White said.

Frontier customers and lawmakers described numerous problems. Utilities & Commerce Committee Chairman Mike Gatto, a Democrat from Los Angeles, read a letter from a customer who lost phone service for 16 days. The customer spent hours on hold across numerous phone calls. This customer and others reported that Frontier employees didn't show up to scheduled appointments.

"I've got a stack of letters like this," Gatto said.

The state Public Utilities Commission (PUC) is also to blame for not properly overseeing the transition, said Jim Patterson, a Republican lawmaker from Fresno.

"This is a failure of the fundamental role and responsibility of the PUC," Patterson said, speaking to PUC Executive Director Tim Sullivan. "As much as frontier has an obligation to regain their customers' respect and appreciation, you have a big job repairing it with the members of this committee as well."