At long last, a Silicon Valley startup has built something truly useful: a bot that will fight with Comcast reps for you.

Trim, a San Francisco startup whose service cancels recurring subscriptions you don’t want, has built a bot that logs into your Comcast CMCSA account, and attempts to lower you monthly bill. The bot is programmed to converse via chat with Comcast customer service reps using a set of arguments and responses Trim has determined work often enough to successfully decrease a monthly bill or get you a one-time credit.

“My grandmother was overpaying by $35/month for Comcast, because they had raised her rate a little bit each year for the past decade,” Trim co-founder and CEO Thomas Smyth tells Fortune . “I negotiated my grandmother’s bill (saving her $420 per year) and wondered if there was a way to do that automatically.”

Get Data Sheet, Fortune’s technology newsletter.

To use the bot, download Trim’s Chrome web browser extension, then follow the instructions, including filling out your Comcast account information, which Trim’s bot will have to supply to the customer service rep. While the bot battles with Comcast, you can play games by clicking on the game icons on the left of the screen.

Of course, there’s no guarantee right now that Trim’s bot will be successful. The company has been testing it for about a week now and approximately 200 people have used it. So far, it’s had a 70% success rate at lowering customers’ bills, with an average saving of $10. Trim isn’t taking a cut from the savings, which means you can keep all the extra money for yourself.

The startups says it’s working to add more functionalities to the bot so that it can chat with a Comcast rep if your Internet service it too slow, or there’s an outage.

For more on bots, watch :

While bots—computer programs designed to chat and interact with humans—have been getting a lot of attention lately with companies like Facebook fb investing a lot in that area, many are still clumsy and a gimmick.But Trim’s Comcast battling bot turn out to be a helpful and clever use of that technology and we may see it used more and more to in the case of customer service issues.

When Fortune spoke with Michael Schneider, whose startup Service handles people’s customer complaints to airlines and such, he said that while humans are currently doing the work, bots will likely take over certain customer complaints that are common and can be automated.