Plugin is messing up wpsc-single-product.php

Hi,

My site was working perfectly a while ago, but I started to get calls from users because the single product pages were broken. When I checked, they were looking like this: http://img.photobucket.com/albums/v142/psychocynic/misc/01_zps04e23db2.png

The product title, product photo, quantity & size inputs, the add to cart button and the plugin have all disappeared and the styling is broken also.

I contacted my theme developers and asked where the problem was coming from. They replied that the problem seems to be coming from the WPEC Related Products plugin. I tried deactivating and deleting the problem and this is what happened: http://img.photobucket.com/albums/v142/psychocynic/misc/02_zpsb6e84f0f.png

Now the logo, menu, header and footer are gone and the styling has gone back to the default template. The developers told me to contact the plugin developer.

Why is this happening and how can we fix it? We’re missing sales because of this. Your help would be most appreciated.

http://ww.wp.xz.cn/extend/plugins/wpec-related-products/