If you cannot find the feature that you want, please create a support ticket.
If something does not work perfect, you can turn off it then also create a ticket:
https://treedify.freshdesk.com/support/tickets/new
Anyway if you must uninstall Selly, you can click uninstall app in Shopify admin:
If your store has a vintage theme, Selly has a small snippet. Although it does not affect your store performance, you can easily delete it by 2 simple steps:
1) Open the file theme.liquid
2) Delete this text {% render 'treedify' %} and also delete this text {% render 'treedify_script' %}
If you need further support please create a ticket: