Level 3 ( LVLT) plunged 17% after the telco slashed its cash flow guidance for the next two years.The Broomfield, Colo., company said growth in customers' use of its services has failed to keep pace with network upgrade expenses. "While we continued to grow Core Communications Services revenues and we did meet our guidance measures in the third quarter, the company had difficulties with provisioning orders for its services," said CEO James Q. Crowe. "The breadth of the problem was greater than we had earlier diagnosed, and we did not increase provisioning capacity as we had expected." As a result, Level 3 cut its 2007 guidance for consolidated adjusted earnings before interest, taxes, depreciation and amortization guidance to a range of $813 million to $833 million, from the previous guidance of $860 million to $920 million. For 2008, Level 3 trimmed its expecation on adjusted Ebitda to a range of to $950 million to $1.1 billion, from the earlier $1.15 billion to $1.3 billion. "We are disappointed by our performance, particularly given the strength of the current market," Crowe continued. "We believe we have identified the underlying causes of our provisioning constraints, and we have begun to implement additional changes. We are focused on correcting this issue as quickly as possible." The news comes just a week after the company announced the departure of its financial chief, Sunit Patel, and completed the acquisition of certain AT&T ( T) assets that were divested as a result of the merger between AT&T and BellSouth. Level 3, which provides wholesale data transport to big telcos and cable companies like Alltel ( AT) and Comcast ( CMCSA), saw its shares fall 76 cents to $3.56 after earlier hitting a 52-week low at $3.46.