Vinted complaint: False allegation

I have an account with Vinted. Yesterday I agreed to sell a pair of jeans within the app to someone who said they would pay me yesterday if I agreed to a significant discount. It suited my plans as I wanted to post this morning. The buyer then didn’t purchase the jeans in line with the agreement. There was no functionality in the app to cancel the agreement and no way of contacting Vinted about the issue. An item that is pending payment does not appear as an item with a link through to the help centre. I did the only thing I could and deleted the item for sale. No payment had been made for the item and no notification from Vinted to say payment had been made. All of the actions and comms were within the app. I had a notification today from Vinted basically accusing me of making an arrangement outside the app (I didn’t) and accusing me of fraud. There is not a single way I can contact Vinted about this issue which is crazy!!!