Customers of a Fremantle travel agency have reported being left stranded in Europe, having their flights and accommodation cancelled and receiving foul-mouthed abuse from the company on Facebook.

The Consumer Protection agency in Western Australia issued urgent advice about Sky Air Services after receiving complaints from 51 customers.

The agency said the Fremantle company was in financial trouble and customers were estimated to have lost about $175,000.

It said while most customers were yet to travel, eight were "currently in Croatia or Serbia with no confirmed return flight".

Sky Air Services' Facebook page detailed a litany of customer complaints and some colourful responses from the company.

Warning: This story contains strong language

"You are a f***ing pain in the ass hard maintenance anyways! good riddance and bon voyage!!" the company wrote in response to one woman's complaint.

Another person who complained about high prices received a response that read: "Inflated price? u mean 20dollar commission? ... we can take your 20 dollars and wipe our butts with it!"

The agency's Facebook page has since been taken down.

Consumer Protection said customers had turned up at airports but been unable to board flights because they had been cancelled due to non-payment, or never booked.

One young member of the Melville water polo team had been unable to return from Europe, and the club eventually had to pay $2,000 for new flights back to Perth.

Consumer Protection commissioner Anne Driscoll said the agency's customers were urged to contact airlines and accommodation providers directly to confirm their bookings.

"I also encourage those affected to contact Consumer Protection so we can get an accurate picture of the number of consumers affected by this situation and keep them informed of developments as they occur," Ms Driscoll said.

"Consumers who have made a booking using a credit card and not received what they paid for should seek a chargeback from their card provider.

"Unfortunately those who have paid by direct bank transfer may not be able to access redress in this way, which serves as a reminder not to pay for travel services in this way."

Customer says she is $4,900 out of pocket

Customer Sonja Hlevnjak said one of the owners of the travel agency had called her last September to offer her a good deal on flights to Europe.

"She said 'you need to pay today or tomorrow because those prices won't last very long', so I paid for the tickets then," Ms Hlevnjak said.

Notices from Consumer Protection have been posted on the windows of the Sky Air Services office in Fremantle. ( ABC News: Charlotte Hamlyn )

"In January I asked for my booking reference and everything and she said everything is good.

"So I was under the impression everything was all paid for and everything was good.

"But this week I heard people start talking about how they couldn't get their tickets, and a friend called me asking if I had mine."

Ms Hlevnjak said she called Sky Air Services to try to confirm her flights and sent text messages, but did not get a response.

When she called the airline, she was told she had a booking but that the flight had not been paid for.

"I tried to contact both owners of the travel agency but no-one is answering the phone," she said.

Ms Hlevnjak said she had lost $4,900.

Customer in limbo on eve of trip

Another customer, Enez Maric, said he was supposed to be flying out with Qantas today for a two-and-a-half month trip to the USA and Europe.

He said he booked and paid for the flights and his accommodation through Sky Air Services two months ago, but was not aware of any problems until seeing media reports about the agency this morning.

"And I came here [to the agency] just a few minutes ago to check and I found out the door is closed," he said.

"I paid almost $10,000 for tickets and almost $12,000 for hotel accommodation. That's without any food or anything.

"[The] last two emails [the agency] didn't answer at all, and I didn't know what's happening. I thought everything was alright, but my flight's this morning at 10:10 and I don't know anything at the moment.

"So I am going to Qantas straight away to find out. Even if I have to pay new tickets rather than stay at home.

"I've been waiting for this holiday for three years."

Sky Air Services has been contacted for comment.