(12:48 p.m. EDT) -- Port Promotions, a company that sells shore excursions independent of the cruise lines, has ceased operating and filed for bankruptcy, reports Travel Pulse, a travel news Web site.

The company filed for Chapter 7 on September 9, 2013, which means the company is liquidating (as opposed to reorganizing under Chapter 11).

Travel Pulse reported travel agents suspected something was not right even before the official filing because they could no longer reach anybody at the usually responsive company. We called the company's 800 number on Thursday, but the general voicemail was full. However, the Web site remains operational; when we tried to make a sample shore excursion booking online, we got all the way through to the credit card prompt without any flags.

Travelers who booked through Port Promotions but not yet sailed should contact their travel agents and collect all receipts and documentation, as you may need to contest charges with your credit card company.

We'll keep you posted.

--by Erica Silverstein, Features Editor