Damage to the Commodore Clipper ferry, which struck the seabed off Guernsey on Monday, is worse than originally thought.
All sailings are now cancelled until 27 July.
The vessel is in dry docks in Falmouth, Cornwall, for a safety inspection and repair.
The Commodore Goodwill is delivering essential freight as usual and less urgent shipments on a delayed basis.
The Clipper and Goodwill carry freight, vehicles and passengers on an 11-hour "slow" sailing between Portsmouth, in the UK, and the Channel Islands.
A fleet of three faster ferries mainly carry non-commercial cars and passenger traffic.
Condor boss James Fulford said passengers booked on the Clipper would be accommodated on the fast ferries.
He urged customers with bookings after 27 July not to contact the company until further updates.
"I'd like to apologise for the inconvenience and concern that our passengers will feel and to reassure people that we are working tirelessly to resolve this situation," he said.
St Peter Port harbour master Chad Murray said Guernsey authorities were investigating the incident with the UK's Marine Accident Investigation Bureau and the Flag Administration of the Bahamas, where the vessel is registered.