Update not working

I have been trying to update the Premium version of this plugin since version 4.1.1, and I have finally given up. Their in-built update function doesn’t work (while other plugins up-date without any problems). There is no support site for any problems you run into with this plugin, so there is no way of getting any help! What a joke for a supposedly “premium” product.

I paid good money for a product that doesn’t work. I have now uninstalled it, and suggest everyone stay clear of this plugin.

https://ww.wp.xz.cn/plugins/wordpress-seo/