Minnesota Attorney General Lori Swanson slammed Comcast Corp. on Friday, alleging in a lawsuit that the cable TV and internet giant overcharged customers for cable packages, charged consumers for unordered services and didn't deliver the prepaid Visa cards promised in its promotions.

Comcast, also known by the brand name Xfinity, added home security, service protection plans, modem and other equipment charges to customers' bills without authorization, Swanson told reporters.

To lure some customers, Swanson's office said Comcast promised prepaid Visa cards of $200 or more if they remained in the minimum-term contract and up-to-date on monthly payments for 90 days, but did not deliver.

"It's hard to shop for cable television if a company plays hide-the-ball on its true prices, and people shouldn't have to watch their bills for things they didn't buy," Swanson said in a statement.

The lawsuit filed in Hennepin County seeks unspecified restitution and civil penalties.

Comcast responded saying it fully discloses all charges and fees and that the facts don't support Swanson's allegations.

"We're fully committed to our customers in Minnesota, and it's important to us to make sure we deliver best-in-class products and services and that our customers understand the products and services they order," said company spokesperson Jill Hornbacher.

The attorney general's complaints go back "several years" and the office "has largely ignored our efforts to work together to address them," she added.