WordPress e-commerce plugin caps total order cost at 999,999,999

I have a problem with an ecommerce website. I am using WordPress, and the ecommerce plugin WordPress E-Commerce.

I do not know much PHP so I do not understand why this is happening.

My problem is that when people place orders that exceed 999,999,999 currency, it cuts off at 999,999,999. For example, If somebody bought 2,400,000,000 worth of items, it would cut off at 999,999,999 for each item.

Does anybody know why this happens? or a workaround to fix it?

From what I see in the PHP files, this is the code used to compile the “Total Price”.

$total = 0;
$shipping = $row['pnp'];
$total_shipping += $shipping;

$total += ( $row['price'] * $row['quantity']);