Its claimed staff at a Western Road travel agent were told on Sunday the company had gone into liquidation.
Now they are concerned about clients who might be worried or need help and advice.
Five employees were sent an email at 9pm informing them ME Travel was closed and that liquidators had been appointed.
The travel agent was owned for many years by Mike Ellis but was sold to a company based in Dartford.
Jackie Packer, who started there in 2000 but left for a while before returning to work, claimed staff members were aware of problems which became more obvious when ABTA recently stepped in.
She and the others discovered the locks at the premises had been changed when they checked on Monday and they cannot get inside to pick up personal belongings.
She commented: “I am just worried about my clients. We are with ABTA so everyone’s money is protected, but given the age of some of our clients, they will need the number to find ABTA or to get some help.
“I am quite angry. I was a bit shellshocked but I suppose we expected it. I feel so dreadful for the clients - I don’t want people to think we had any part in this. We can’t help them - obviously we now don’t have access to any of the files, and we can’t get into the shop. We didn’t realise we would likely be locked out.”
A colleague added: “I just feel so bad for the customers.”
An ABTA spokesman stressed that customers would not lose out and added: “ABTA is currently looking into the trading status of ME Travel. ME Travel is an ABTA member holidays and should not be affected. Concerned customers should contact their tour operator directly.”