South Carolina customers of a Florida company might lose telephone service.

DialTone & More Inc. sells local calling plans in 25 counties — including Berkeley, Charleston and Dorchester — by leasing parts of AT&T's telecommunications network. It has about 5,700 customers statewide.

But AT&T has notified the company and the S.C. Office of Regulatory Staff that it might pull the plug on their business arrangement on March 1. The reason was not specifically disclosed in a statement issued today by the state agency, which said representatives of the company have not responded to its inquiries.

A lawyer for the Office of Regulatory Staff filed papers in January to revoke the certificate that allowed DialTone & More to operate as a utility in South Carolina.

The reason was that the company had not been contributing as required to a fund that subsidizes phone service in rural areas. The office said the amount owed as of Jan. 11 totaled than $34,000.

Officials at Melbourne, Fla.-based DialTone & More could not be reached immediately for comment today.

The company's South Carolina customers with questions can reach the Office of Regulatory Staff at 800-922-1531.