Members of the platform have expressed outrage after an update resulted in listings displaying inaccurate size information.
The second-hand shopping app has revised its sizing categories 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 an altered size classification versus the original listing as a result of the reclassification.
The company said the revised method more closely matches other platforms.
They have suggested members to review their products and adjust the sizing manually where appropriate, causing user dissatisfaction.
Before the change, the sizes had both numerical and alphabetical indicators, like S/8 or M/10.
The updated approach includes a letter with a size spectrum like S/UK 8-10.
In some cases, the size labels have been reassigned - like an L measurement used to be a 12 but is now a UK 16-18.
One content creator, who produces content about larger sizing, said the change "makes both selling and buying harder".
"Rarely do manufacturers list XL as sizes 20-22," the way the service now categorizes.
Stephanie Gallen, from Glasgow, stated items she posted with size 14 tags were displaying on the service as size 20–22.
"If anyone [who is] size 20-22 buys them they may become frustrated," she said.
Another shopper, from Derby, explained she became annoyed by the change as she had to manually change the sizing for "all her products".
"This situation is especially annoying, because of my ongoing medical condition and selling on Vinted has been paramount after experiencing income reduction," she stated.
The platform boasts over 100 million shoppers, with 18 million British users.
It has emerged as a preferred choice versus similar marketplaces including eBay and Depop.
This represents another occasion that an unexpected update on the platform has faced criticism: previously, the service retracted a modification concerning shipment methods following member complaints.