Irish Ferries could face a multi-million euro compensation bill - after cancelling summer sailings to France.
It has thrown the travel plans of 19,000 holidaymakers into disarray - with many taking to social media to voice their anger.
The company says it is contacting all customers to offer them refunds or alternative travel options - but admits a dedicated helpline is extremely busy.
Consumer Expert Dermot Jewell says the controversy could have a huge impact on the Irish Ferries brand.
"It very much depends on how they manage it, that's what people are going to remember. 'It was an awful situation but we walked away happy'.
"If it is the reverse 'A terrible situation and it was utterly devastating throughout with a poor remedy' that's what will be remembered.
"So it is how they manage it and most importantly how they compensate for it."
Irish Ferries have said that they are working through calls, emails and messages as quickly as possible and have thanked customers for their continued patience.
Customers who have been affected by the cancellation of sailings on the WB Yeats vessel are encouraged to call ROI: 0818 300 400 or UK: +44 8717 300 400 or email firstname.lastname@example.org.