The death of a businessman who ran coach tours has led to holidays being cancelled and uncertainty about the return of customers' deposits.
About 100 to 150 customers have been affected by the death of the man who ran Leisurebreak Holidays and Leisure Breaks with A1, in Lancing.
West Sussex trading standards said the business in Station Parade offered coach trips to UK destinations.
The man's bank accounts are currently frozen and an inquiry is under way.
West Sussex County Council said it had not released the name of the businessman who died out of sensitivity to his family.
A spokesman for trading standards said the coach trips were to destinations such as Bournemouth, the Cotswolds and Scotland.
Each trip cost up to £200 for a four or five-night stay, and customers paid deposits of between £30 and £60, some of them booking more than one trip each.
Trading standards said the sums involved represented a large sum of money for some of the customers who were mainly retired and in their 70s and 80s.
Head of regulatory services at the trading standards department, Graeme MacPherson, said: "The owner's death has resulted in many planned trips being cancelled and doubt over the return of deposits to customers who had already booked."
Councillor Peter Evans, cabinet spokesman for public protection, said: "Because booking a holiday represents a considerable investment for people looking forward to a well-earned break, our trading standards service began the investigation as soon as they were made aware of the situation."
Officers said they were alerted to the issue after receiving a complaint from a customer through Consumer Direct. They subsequently discovered that the owner had passed away.
The man who died operated as a sole trader and so there was no-one to take over the running of the business, they said.
As a tour operator with a shop front, the man would have paid for accommodation, coach hire and excursions and sold the holiday as a package tour.
Under the man's obligations in running package tours, he should have had money in a fund under a financial bond scheme which would have offered protection for customers.
Inquiries are still under way into whether such protection was in place.
Cheques received by the business after the man's death have been returned.
So far, about 10 final balances have been refunded, and up to 20 people have had some sort of refund.
About 50 people have already been contacted by trading standards, and anyone who was due to travel with either of the two companies affected has been asked to contact Consumer Direct.