Hello,
1) I see the brand filter on the shop page https://gyazo.com/ed59e0ddf2f8152af4dde88240486d4c and it filters the products. Could you, please, explain the problem in more detail? Maybe provide screenshots for better understanding. Also, provide temporary WP Dashboard and FTP access to your site to check the issue after that.
2) Could you, please, explain in more detail problem with the h2 tag?
Regards
Regards