YANBU at all, @ProductivePenny
There are some massively over-entitled, impatient people around, including on this thread 👀
It would never occur to me to even contact a seller before the five working days specified by Vinted are up. That's the deal, and people have lives to manage, just like I do. It's not the platform to buy things if you want them 'next day', and anyone with those expectations is an idiot.
I did once buy something that was never sent, and even then I didn't harass the seller, because when I looked closer they hadn't been sending anything out at all and clearly weren't using Vinted any longer, so my money was automatically refunded. I learned from that experience to always check a seller's feedback - if I had done that, I could have seen the issue and avoided the hassle. Yes, that seller may be an arsehole, but it doesn't help anyone if I were to bombard them with messages.
Conversely, most sellers are lovely, in my experience, and keep me updated as to when they send things. I had one apologise recently because she couldn't send the item the same day through no fault of her own, and I replied, as always, that it was no problem and I was in no hurry. That's how it should work. I do give very good feedback to people like that and make sure I thank them, but I also give good feedback to people who send things out within the timeframe specified by Vinted as they are doing what is agreed when I purchased the item. People need to calm down and stop being so entitled.