Gumtree the company is a scam. They market the Gumtree site as free to post adverts, but if you do not pay to bump your advert, they block you as a user. There is no customer support to discuss being blocked. They should be investigated.
I have have been using Gumtree for years. Now, every time I try to post an ad it says, "Your ad has been removed from the site because it breaks posting rules. We've emailed you to explain why." I do not receive an email from them to explain why. The items I sell are not restricted and I have used the site for similar items in the past (e.g., child stroller). Also, for some reason, all of my previous posts (i. E., successful sales) on Gumtree have also been listed as "removed" under Manage my ads.