Shopping Cart Fix

We have a shopping cart vendor that is not responsive and their lack of action could be an opportunity for you. The shopping cart is from [login to view URL] and is programmed in Perl – a language our developer is not familiar with. Please show us projects in your portfolio that are Perl programmed to do what you can in your response to prove you are an expert. If we do not hear back from our vendor by 10am central US time on Monday, we will begin to contact freelancers that seem capable of the project so DO NOT BID IF YOU ARE NOT AVAILABLE DURING US WORK HOURS ON MONDAY. Here is the issue: At any point of the order process in the cart, if you hit the “back” button, it doubles up the order. They have received complaints on this in the past as well. First, is there a way to fix that error? If not, what would you suggest adding to make it easier for the customer to move around within the cart without messing up the quantities?