I've been using Vinted for a while now. Sold loads, bought a few things too.
I saw something I was interested in and I asked for another photo. Let's say it was a jumper and I wanted to see a photo of the back.
Seller didn't respond for 2 days. Ok fine, she replied saying that she'd get a photo. I waited until the following evening, still no photo.
At which point I thought sod it, I'll take a chance as I do want the item. I made an offer. It was £30 and I offered £25 so not a ridiculous offer I don't think. She's completely ignored.