Five UK broadband and landline providers will now automatically compensate customers when services do not work.
From Monday, customers who experience delayed repairs, installations or missed engineer appointments will be compensated, without having to ask.
BT, Sky, TalkTalk, Virgin Media and Zen Internet have joined Ofcom's scheme, which is not compulsory.
Hyperoptic, Vodafone, EE and Plusnet have also committed to the plans.
According to industry watchdog Ofcom, there are 7.2 million cases each year where broadband or landline customers suffer delayed repairs, installations or missed appointments.
Previously, only about one in seven broadband or landline customers received compensation from providers for these delays.
Ofcom consulted on enforcing formal regulations regarding compensation of broadband and landline services in 2017.
However, some service providers then approached the regulator independently and offered to pay compensation to customers.
This led to Ofcom releasing details of its voluntary automatic compensation code of practice in November 2017.
"We think it's unacceptable that people should be kept waiting for a new line, or a fault to be fixed," said Ofcom's chief executive Sharon White.
She added that the new rules would provide an incentive for service providers to want to avoid problems occurring in the first place.
"But if they fall short, customers must be treated fairly and given money back, without having to ask for it," she said.
TalkTalk, Sky, Zen Internet and BT all use BT's Openreach network to provide broadband and landline services.
In December, the providers agreed a deal with Openreach that if any delays to repairs or installations occurred, Openreach would compensate the providers.
The providers would then use that money to automatically compensate their customers.
Under the terms of the agreement, if an engineer does not arrive on schedule, or cancels within 24 hours, the compensation will be £25.
If a service stops working and is not fully fixed after two working days, customers will be entitled to £8 a day in compensation.
There will also be £5-per-day offered for new services not starting on time.
Hyperoptic and Vodafone will begin automatic compensation later this year, while EE plans to start paying compensation automatically in 2020.
Plusnet has committed to the scheme, but has not provided a timescale for when it will begin providing automatic compensation.
Asked why Ofcom had chosen not to implement formal regulations for automatic compensation, an Ofcom spokesman told the BBC: "This is the quickest way of putting money back in people's pockets. All the largest firms have committed, with more than 95% of households covered."
He said that customers with providers not in the scheme from Monday could choose to switch to a new provider if they were unhappy with their current service.
However, Ofcom added that it was keeping "a close eye" on the firms in the scheme.
"If they don't comply, we'll step in and take action," the spokesman said.