Hi Stefanie,
Sorry to hear that there are troubles with the plugin.
Sure, refund is not a problem, however, maybe I can try to help you? The plugin should be compatible with the Gutenberg editor – if you wish, I could log in to your site and check what’s going on (my email is [email protected])? By the way, did you try using our [alg_back_button] shortcode?
Please let me know if I should proceed with the refund.