As the guide you buy is a digital product which you download on your computer, it cannot be returned. You may ask for a refund within 30 days from the date of purchase. I may give you refund only if you are able to convince me that the guide is not useful or helpful to you in any way or if you are able to prove to me that you have taken efforts and actually implemented some things mentioned in the guide and it did not work for you.
There are some people who use refund as a way to get the digital product free of cost so I would not honor all the refund requests that I get. If the refund request seems genuine to me then only I will offer a full refund of money, if the refund request is made within 30 days from purchase date.