Hmmm... I have had a few issues with my Surface not responding after waking it from connect standby. But other than that did not have any issues. Another user from this site has had issues with his screen not responding in a certain section. See
http://forums.windowscentral.com/mic...een-issue.html.
I don't have a solution for you but I'm not sure why you would sell this yet. The Surface Pro 3 is under manufacture warranty for the first year. Call Microsoft and get it replaced. Or better yet since you have had it for only 5 days you could even try replacing it from the retailer you bought the device from or just return it. Most store policies tend to be 15 to 30 days. Don't waste your time or lose money trying to sell it yourself. Hopefully you can get the issue resolved.
Hopefully this was somewhat helpful!