Hi Jarno, ok you’re using Elementor. That changes things a bit. Can you try this code instead:
@media (max-width: 768px) and (min-width: 420px) {
.elementor-widget-container .woocommerce .wc-columns-4 ul.products li.product,
.elementor-widget-container .woocommerce-page .wc-columns-4 ul.products li.product,
.elementor-widget-container .woocommerce-page.columns-4 ul.products li.product,
.elementor-widget-container .woocommerce.columns-4 ul.products li.product {
width: 48%;
margin-left: 2%;
float: left !important;
}
}