Issue with expired delivery settings when clients stay on the checkout page for too long

Hello,

We are a bakery, all products are made fresh, and we deliver every hour.

I use Zapiet app for handling delivery by the hour.

What happens is that customers stay on the checkout page for too long, and they end up placing their orders with an expired chosen time for delivery, sometimes even after the bakery is closed, but since they are already in the checkout, the order gets through and everyday we have a lot of customer service to do…

Is there a workaround?

Zapiet is telling me since 2 years that Shopify controls the checkout and that nothing can be done but the user experience of our store is not great because of that.

Thanks.