Only around one in seven broadband or landline customers who suffer delayed repairs, installations or missed engineer appointments have received compensation from their provider, and even then, only in small amounts, Ofcom said.
The media watchdog has intervened and the largest broadband and landline providers have agreed to compensate customers when they experience these delays.
Ofcom chief executive Sharon White said: "We think it's unacceptable that people should be kept waiting for a new line, or a fault to be fixed.
"These new protections mean phone and broadband firms will 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."
BT, Sky, TalkTalk, Virgin Media and Zen Internet had already signed up to the scheme, Ofcom said, adding that Hyperoptic and Vodafone have also agreed to the new terms, and will start paying compensation automatically later this year.
The firms that have committed account for more than 95% of broadband and landline customers in the UK.
As well as consumers, it will benefit the many small and medium-sized enterprises (SMEs) who choose residential landline and broadband services.