Being aworn at and sent rude messages

I have encountered a lot of rude people on Gumtree, both customers and sellers. In one situation, I was looking for a psychology textbook to buy and I came across this guys that sells pdf textbooks and I enquired to him through WhatsApp about the textbook that I wanted. Mind you, I was just making an enquiry and didn't make any promises to purchase the book. After a few months he contacts me on WhatsApp asking me if I am still interested in buying the book? I said I am no longer interested. After that the asshole sends me an ugly message where he swore at me for not informing him earlier even through I never gave any promises to buy anything and then blocks me completely.

In another situation, I posted an ad to sell a DVD player. After a few months I had already sold it but there were other people who expressed interest but told them it's already sold. This gumtree user, JJ, asks me if the DVD Player is still available and I told him it's sold already. He told me I should take the ad off. I said I already told him it's not available and that there is no need to take it off since it will expire in a few days anyway. The idiot then starts sends me rude messages and swore at me as well and I then asked him what was his problem. Everybody else had no issue with it already sold but this guy made a really big deal out of it!

I don't think I will post anything again on gumtree nor can I trust it as there are many rude psycho idiots here that are just not trustworthy and seem to get offended for not getting what they want.