How long to resolution?

I’m fairly new to Vinted but have had a couple of good experiences as a buyer. Had my first negative one. Recently bought a dress listed as new with tags. It was only £30 so thought I was getting a bargain. It arrived - really dirty and with a hole right in the middle at the front. I raised it as something is wrong, said I didn’t want a dress with a hole in it, the seller responded offering a £5 refund, which I refused, then offered £10 refund and said “no disrespect, but you could just sew it up” I explained again that I didn’t think it could be repaired (it’s a jumper dress, I can’t just fix a hole in the centre) and they ignored me. Waited a couple of days and raised to Vinted with pics etc and they said the seller had 48 hours to reply, the seller then offered a £15 refund, which I’ve refused again as the dress is only bin-worthy, I don’t want to pay anything to keep it. But they’ve wasted 48 hours before offering that - how long can they go now before Vinted actually step in? Also why are people so scammy. 😞