Current customers, some of whom have been posting on CNN.com, are having trouble reaching the company in some cases.

"What about those of us that got our cruise canceled?" wrote one commenter, who said she was scheduled to sail on the Carnival Dream. "I haven't heard anything from Carnival, and I don't know how long it will take to get a refund. Now we are stuck not knowing what to do for a vacation we saved 8 years to take!"

Still, Connie Hammond is one of those Carnival fans who isn't giving up on the cruise line.

"All three of my prior Carnival cruises were wonderful, food was outstanding, ports were well organized and safe, shipboard activities were plentiful, all for a small budget price," Hammond, a resident of Fort Madison, Iowa, wrote in an e-mail.

"I'm sure I could have paid $1,000 more per person and been impressed much more, but the Carnival cruise was a great vacation and a memorable fun time."

Hammond said she expects the recent incidents will be a wake-up call for Carnival's maintenance program, but she's not concerned about safety.

She's already booked her next Carnival cruise, taking her 79-year-old mother and a girlfriend who has never been on a cruise.