Shoppers are voicing their frustration due to a modification that led to products showing incorrect sizing.
The second-hand shopping app has revised its size classifications for women's and children's clothes failing to inform all users about the change.
Numerous buyers and vendors are posting online stating that platform listings now display a modified sizing category versus the original listing due to the recalibration.
The platform stated the updated approach better aligns with other platforms.
The platform has recommended to review their products and adjust the sizing manually where appropriate, which has left users frustrated.
Previously, the sizing featured numerical and alphabetical indicators, like S/8 or M/10.
The new system has a letter and a range such as S/UK 8-10.
In some cases, the sizing has been recategorised - like an L measurement used to be a 12 but now shows as UK 16-18.
One content creator, who creates plus-size fashion videos, said the change "makes both selling and buying harder".
"Few clothing companies classify XL as 20-22," which is what Vinted now does.
Stephanie Gallen, from Glasgow, 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 explained.
Another shopper, based in Derby, explained she became annoyed due to the update requiring manual adjustment the sizing for "all her products".
"This situation is especially annoying, as I'm chronically ill and selling on Vinted has been paramount following partial earnings loss," she stated.
The service features exceeding 100 million members, comprising 18 million UK members.
It has become a favored option versus similar marketplaces including eBay and Depop.
This is not the initial instance where an unanticipated change on the platform has faced criticism: previously, the platform withdrew an update concerning shipment methods after backlash from users.