Hundreds of houses have been left without landlines and internet since Tuesday due to cable thieves.
Those affected are not set to have their services restored until next Wednesday after thieves dug up cables in Southbridge Place, Croydon, on Tuesday.
BT, which operates the cable, says the process to fix the problem is complex although some of those affected have had their supplies restored.
It has also put up a £1,000 reward for anyone who helps catch the culprit.
Gordon Glover, of Tritton Avenue, said: "It's inconvenient to say the least. If anyone sends me an email, I can't look at it. I've been trying to find out what's going on but with BT and Talk Talk it seems like one hand doesn't know what the other's doing."
A spokesman for BT said: "We have suffered cuts to underground cabling in an apparent attempted theft which is affecting some services in the area at the moment.
"We have now brought in replacement cabling, carried out repairs and are now on the complex process of jointing those affected back into service.
"We have now restored some those affected and this will increase as work progress around the clock. We are doing all we can to get this all completed as quickly as possible, but it is likely to be well into next week before absolutely everyone is back in service."
BT and Crimestoppers are offering a £1,000 reward for any information which leads to a successful prosecution. People with information can call Crimestoppers on 0800 555 111.
Have you been affected by the problems? If so, contact reporter Mike Pyle on 0208 722 6359, email email@example.com.