You can post a message on your paypal account that will be seen by all your customers who want to open a paypal dispute...So before opening a paypal dispute your customers will see your message...you could post something like:
Your satisfaction is our top priority. If you have a problem with a transaction, just contact us at email@email. We will make every effort to respond to all inquiries as fast as possible
To edit this message you just need to go to: profile/more options/Selling Preferences/Customer Service Message
Hope this helps...