Tesco customers were left without their grocery deliveries on Sunday morning after a technical fault prevented many orders going out.
Dozens took to social media to express their frustration, branding the experience and lack of communication a "shambles".
A spokesperson for the supermarket apologised for the inconvenience.
Tesco said orders were back up and running by mid-afternoon.
But disgruntled Tesco shoppers were put out that there had been so little information from the company while they waited in for orders that did not arrive.
Reports of problems peaked at 09:00 on the Downdetector website, with thousands of users logging problems with Tesco's service.
Tesco's spokesperson said: "We're really sorry that due to a technical issue, we had to cancel some online orders today.
"Our technical team have worked around the clock and have now fixed it."
"Customers who were impacted have been contacted directly. We apologise again for the inconvenience."
Tesco advised customers to rebook to have orders delivered in the coming days. However, some customers said they were struggling to find suitable slots.
The UK's flagship share index, the FTSE 100, was up 27-points at 7,489 shortly after opening this morning.
Brent crude oil futures were down 0.29% today, trading at $78.33 a barrel.
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