Sean Fothersgill, the owner of model car seller Pendle Slot Racing, typically gets about 50 orders a day from outside the UK — or about half his total. 

For the past week, those international orders have been gathering dust in a corner of his warehouse. Royal Mail, which Fothersgill relies on for shipping, told customers on Jan. 11 to stop posting items overseas following a debilitating cyberattack. 

The glitch has left businesses across the UK unable to send parcels internationally, leaving furious customers demanding refunds and hamstrung companies such as Pendle Slot Racing — which sells Scalextric race cars — at risk of losing out to rivals. Royal Mail has started moving a limited number of export parcels as it tests “operational workarounds,” it said Wednesday, but continued to ask customers not to submit new packages. 

The cyberattack is only the most recent cause of aggravation for Royal Mail customers. Sporadic strikes over pay and conditions in recent months disrupted deliveries for online retailers such as Asos Plc over the Christmas shopping season. Electronics retailer Currys Plc dropped Royal Mail for its small-box home deliveries in favor of DPDgroup to lessen the impact of the strikes. 

“We’ve been in business for almost 30 years, but this has been the worst two months of dealing with the Royal Mail in all that time,” said Fothersgill, whose business is based in northwest England. “We’re missing out on orders.” 

Adding to frustration related to export deliveries, Royal Mail, the UK arm of International Distributions Services Plc, has given scant detail on the attack or when the situation will improve. 

Chief Executive Officer Simon Thompson told a House of Commons panel Tuesday that no data breach had occurred, but said the company had been advised that discussing fine or additional details of the situation would be detrimental to the investigation.

Even when Royal Mail does resume international shipping, the backlog will bring further delays — causing more customers to go elsewhere for their orders. “At the moment I’m looking at sacks of mail which we’ve had to hold back,” said Fothersgill. “The only thing that could make it worse is if they went on strike again.” 

Sam Cornwell’s Solarcan, a seller of pinhole cameras based in the Scottish Borders, gets about 70% of its orders from overseas. The halt to international parcels has crippled the business, after delays over the past two months had already dented orders. 

“We’ve got about 40 parcels still missing,” said Cornwell, who described the situation as an unmitigated disaster. “Customers can only be sympathetic so far before they start asking for refunds.”