File not found or Downlaoad Link Expired! ampersand Problem

I’m currently working on a website that is selling audiobooks using simple paypal cart but it looks like that when paypal emails out the link that File manager generates the last part of the URL process&did is automatically changed to process& amp;did with the & changing to & amp; (minus the space between & and a). The main problem is using this plugin all of the links generated have process&did does anyone know how to get around the ampersand “&” problem? would really like to know this works before purchasing the pro or web version.