Shoppers are voicing their frustration after an update resulted in items being listed as the wrong size.
This online marketplace has revised its size classifications for women's and children's clothes but did not contact all shoppers about the modification.
Countless users and merchants are posting online saying Vinted listings now show an altered size classification compared to what was initially listed due to the recalibration.
The company said the new system was more in line with comparable marketplaces.
It has advised users to check their listings and manually change the size where appropriate, which has left users frustrated.
Previously, the sizing featured numerical and alphabetical indicators, for instance S/8 or M/10.
The updated approach includes a letter with a size spectrum such as S/UK 8-10.
With some products, the measurements have been reclassified - for example a size L was formerly size 12 but is now a UK 16-18.
A fashion influencer, who creates plus-size fashion videos, said the change "makes both selling and buying harder".
"Not many brands say XL is a 20-22," as the platform currently indicates.
Another user, located in Scotland, explained products she uploaded with size 14 tags were displaying on the service as larger sizing 20-22.
"If anyone [who is] size 20-22 buys them they're going to be very disappointed," she stated.
Charlotte Lunn, located in England, said she had been left angered due to the update requiring manual adjustment the measurements for "each individual item".
"This situation is especially annoying, since I have chronic health issues and platform income has been essential following partial earnings loss," she stated.
The service features exceeding 100 million users, including 18 million in the UK.
It has emerged as a preferred choice compared to resale services such as eBay and Depop.
This represents another occasion that an unexpected update within the service has received backlash: last year, Vinted reversed a change to its shipping options due to shopper criticism.
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