Delivery Fee Issues

Hi,
On my website, I am utilising delivery fee 2.1 plugin.

If a customer selects delivery first, but changes to pickup. On the cart, the delivery fee is removed. However when the customer pays the order confirmation page and the total charged includes the delivery fee.

This is really frustrating my customers.

If they select pickup first, and stay with pickup, this does not happen.

It happens when they select delivery and then change to pickup.

If they select pickup and then change to delivery there is no issue as the fee is then added.

But if they select pickup, change to delivery and then change back to pickup, same issue, delivery fee is still added.

I tried updating to deliver fee plugin 2.4 but when updated it wont allow any transaction to be completed. Pickup or delivery.

The page I need help with: [log in to see the link]