Homes have been left without phone lines for three days after vandals damaged cables in Southgate.
TalkTalk and BT Openreach are working to fix the problem, which has affected homes in Barnet.
Allison McKechnie, who lives in North Finchley, noticed her TalkTalk phone line was not working properly on Sunday.
She said: “My mother who had been trying to get hold of me for two days.
“I work from home so I’ve had to email all my clients to let them know. Luckily I have a mobile, but there are a lot of people who don’t and it will be more of a problem for them.
“It seems strange in this day and age that it takes so long to fix a problem like this.”
A spokesman for TalkTalk said: “Some of our customers in London may be experiencing difficulties making or receiving calls after cables were damaged by vandals.
“We are working with BT Openreach to restore the service as quickly as possible. We are keeping all customers updated on the progress through our website, online service centre and social media.”