A Jersey-based telecoms company claims it has been denied access to the network it needs to connect to Guernsey, the UK and Europe.
Clear Mobitel was granted a licence in 2009 for internet and data services.
Now the company has complained to the Jersey Competition Regulatory Authority about Jersey Electricity and Newtel.
Chris Ambler, the chief executive of the JEC, said it would like to help Clear Mobitel but its fibre optic infrastructure is full.
Mr Ambler said: "We have been able to provide Clear Mobitel with capacity elsewhere in our network.
"The reason we can't provide them with all of their requirements is because we don't have the spare capacity to do that.
"That capacity has already been committed to other telecom operators under contracts that were written more than 10 years ago."
Andrew Elston, from Clear Mobitel, said it had filed a complaint with Jersey Competition Regulatory Authority.