Thousands of UK broadband users are cut off from the Internet because of a row between their supplier and BT.
Services at Euro1Net, based in Kent, were suspended earlier this week. In a message recorded on its telephone line, the company blamed BT for the move, but said it couldn't comment further "due to possible legal action against BT".
BT confirmed on Friday that its wholesale arm had suspended Euro1Net's Internet connection, and said it had little option.
"We had to cut them off because they hadn't paid their bills," said a BT spokesman. "It's not a decision we take lightly, but the situation couldn't go on".
According to BT, the unpaid bills stretch back to April. Like many ISPs, Euro1Net buys wholesale services off BT, and then resells this connectivity to individual consumers.
Around 5,000 customers are affected by the move. If Euro1Net and BT can't find a resolution then it could take them several weeks to transfer to another ISP.
Communications regulator Ofcom is monitoring the situation closely, and is understood to be considering intervening — perhaps to get the service restored or perhaps to help customers move to another ISP.
Last week Ofcom launched proposals to make it easier for Internet users move to another ISP.
"BT Wholesale has the right to cut off any customer that doesn't pay its bills," said an Ofcom spokesman, adding that: "The customers are the most important people as far as we're concerned".