We have products setup using conditional logic that affects the final price.

For example, we have several hair extensions where the customer can select a length and then within that length select their desired color. (see http://superhairoutlet.com/product/machine-weft-%c2%96-italian-wave/)

When you first land on the page it has defaults set, so that initially 14" and Jet Black are selected so the price shows $85. So far so good...

The problem comes in when I select a different price and then change my mind and select a different size. Say I select 14" and then select Light Strawberry Blonde for $90. Then I realize, ooops I want the 18" instead. When I click on 18" the price then switches to $0. The issue here is that it doesn't reset my selection and chose the default I have setup for 18". The bigger issue is that I can now add this to my cart and actually check out with a product with no price and incomplete options.

Is there a way to prevent someone from adding a product to their cart if the total price is 0, or at least to reset the options when a new conditional option is selected?