UPDATE: After publication, we learned Comcast has been making the $20 guarantee for more than two years before this week's announcement. But now the credit is much easier to get. "Customers had to request credits before. Now we're automatically crediting them $20 if a tech is late (GPS triggers it)," Comcast spokesperson Jenn Khoury explained.

Comcast is once again pledging to overhaul its legendarily bad customer service, hiring more than 5,500 new customer service employees and making "major investments in technology and training," the company announced yesterday.

Part of the hiring boost will add "hundreds of additional technicians across the country," with a goal to always be on time for customer appointments by Q3 2015, sometime between July and August. To prove how serious it is, Comcast is making a new promise: "If a technician doesn’t arrive on time for an appointment, Comcast will automatically credit the customer $20," the cable company said.

Of course, Comcast still gives itself a two-hour window for each appointment, but the $20 guarantee appears to be available now instead of in the next quarter.

Comcast said its customer service plan will take multiple years to implement, and it will reportedly cost $300 million. The announcement comes after the failure of its attempt to buy Time Warner Cable, on which Comcast spent $336 million.

Here are some other promises Comcast made:

Comcast will "simplify billing and create better policies to provide greater consistency and transparency to customers."

Comcast this year will open "three new state-of-the-art customer support centers in Albuquerque, NM; Spokane, WA; and Tucson, AZ." The one in Albuquerque will have bilingual staff for Spanish-speaking customers.

Comcast is "tripling the size of its social care team to serve customers more quickly on Twitter, Facebook and other social platforms, and hiring 250 team members to serve in its Xfinity Stores across the country."

Over the next few years, all 500 Comcast stores will be redesigned with "new capabilities, including intelligent queueing that allows customers to reserve a place ‘in line’ from their mobile phone, to cut wait times."

Technicians and call center employees will get better technology, including "a new, cloud-based platform that gives employees a better, holistic view of the customer’s account history so they have everything they need to help customers faster."

All employees, even senior management, will be required to "participate in additional customer experience training every year."

New network management tools will "proactively diagnose issues in the network and enable Comcast engineers to solve them before they reach customers."

Comcast's tech tracker tool, which lets customers track the location and arrival of technicians from their phones, will be available in all Comcast markets by the end of the year.

Comcast's poor customer service was much discussed during its attempt to buy Time Warner Cable, with Executive VP David Cohen admitting to Congress more than a year ago that Comcast is "deeply disappointed" in its own performance. Many awful customer experiences have come to light since then, including billing account names being changed to the likes of "asshole," "whore," "dummy," and "super bitch."