Would-be thieves left 14 homes in Newmarket with no telephone connection after damaging cables.
Offenders lifted a manhole cover in High Street and cut the cables, causing about £5,000 worth of damage, between midnight on Friday and 9am on Saturday.
A Suffolk Police spokesman said the cables were believed to have been damaged in an attempt to steal them.
A spokesman for BT said engineers had visited the site to change a section of damaged cabling and were due to carry out joining work to restore services on Tuesday.
He said:“We have suffered malicious cuts to underground cabling, which has been affecting some services in the area.
“Engineers have been onsite and changed out a section of damaged cabling. Engineers will carry out jointing works to restore services.
“We have had 14 reports of properties that have lost service associated with this incident.”
Anyone with information in relation to this incident should call PC Matthew Jackson at Newmarket Police on 101.
Alternatively, call Crimestoppers on 0800 555 111.