Members of the platform have expressed outrage due to a modification that led to items being listed as the wrong size.
The second-hand shopping app has altered its size classifications for female and kids' apparel failing to inform all shoppers about the modification.
Countless users and merchants are expressing on platforms saying Vinted listings now show a different size category than originally posted due to the recalibration.
Vinted explained the new system was more in line with comparable marketplaces.
The platform has recommended to examine their items and adjust the sizing manually where appropriate, which has left users frustrated.
Earlier, the measurements included one number and one letter, for instance S/8 or M/10.
The revised method features a letter and a range for example S/UK 8-10.
For certain items, the size labels have been reassigned - like an L measurement used to be a 12 but now shows as UK 16-18.
A fashion influencer, who produces content about larger sizing, stated the update "complicates both purchasing and selling".
"Rarely do manufacturers list XL as sizes 20-22," which is what Vinted now does.
A different member, based in Glasgow, said garments she listed on Vinted with size 14 labels were showing in the marketplace as measurements 20-22.
"If buyers measuring 20-22 acquire them they will likely be quite upset," she said.
Another shopper, located in England, said she had been left angered because the modification necessitated personal updates the sizing for "all her products".
"This situation is especially annoying, as I'm chronically ill and Vinted sales have been crucial after experiencing income reduction," she stated.
The service features exceeding 100 million users, comprising 18 million UK members.
It has proved a popular alternative compared to resale services such as eBay and Depop.
This isn't the first time when a surprising modification within the service has received backlash: last year, the service retracted a modification concerning shipment methods due to shopper criticism.
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