extraordinary wait with no feedback

I booked and paid in full for a cruise holiday with Imagine cruising Dec 2015. I have requested to amend the dates of the cruise. I emailed them 11 days ago & provided 2 alternate dates. I was given an incomplete quote for only 1 alternate date. The lady at customer services who helped me subsequently went on sick leave. During the 3 days of her sick leave, I called imagine cruising customer services twice. 2 people promised to help me. No feedback has been received. Yesterday, 10 days after my original email request, the lady returned from sick leave and called & promised to get back to me. Late yesterday afternoon, she emails, saying an \amendment team\" has now been set up who will take over my request. This has become a rather bureaucratic, laborious, time consuming and overall an unsatisfying experience. . It would be unreasonable to accept that a large company like 'Imagine cruising' has only one person working at customer services. It is also unreasonable to wait longer than 7 days for an amendment. Staff are complacent, uninterested and inefficient. I wonder the purpose of the imagine cruising business model, as it may be easier to go directly to the supplier! "