Global Telecoms and Technology was responsible for around 3,500 telephone lines in England. The Greater Manchester-based firm went out of business in February and soon after clients began to report their phone lines had stopped working.
Graham Parrot, of the Aerolite petrol station and garage in Watton, Norfolk, said the lines "just went dead". We couldn't ring in, couldn't ring out and we tried to get hold of Global and we couldn't get hold of anyone at all."
Mr Parrot said his business was "crippled" as it was unable to make or receive calls, and could not process credit or debit card payments.
The regulator Ofcom said it believed that "the vast majority of Global Telecom's customers are able to be reconnected within 24 hours". But a number of affected firms, who lost their connections last week, said they were still trying to transfer to a new service provider and were having to run their businesses from mobile phones.
Meanwhile, it has emerged that the former managing director of Global, Mark Bedward, has set up a new company called Universal Business Technology.
Former Global customers claim they have been contacted by Universal, which is offering to provide telecoms services again.
One businessman said he had signed a contract with Universal as he had been told by another provider that it could take a month to get his telephone lines working again.
Alan McKay, of B & B Skip Hire in Beccles, Suffolk, said he was also told the company would lose the business number it had spent thousands of pounds advertising.
He said that left him with no option but to sign up with Universal. "If we had any choice at all it would be the last option we would take," he said.
Mr McKay added: "I approached Ofcom in London and they said there is really nothing very much they can do to help us, which I find incredible in a very difficult situation."
A spokesperson for Ofcom said: "Should people find that their line has been disconnected they are free to switch to another provider without charge."
Another former client of Global has created an internet forum for other businesses affected by the company's collapse. Barry Taylor, of Loans By Angels, in Manchester, said they were looking at taking a group legal action.
Richard Bligh, Marketing Director at Gamma Telecom told Comms Business Magazine that this was bad news for the channel, “Many ex-Global customer may now be thinking ‘let’s head back to BT because we know they won’t go bust’ and this will reflect poorly on the channel.”