The reality is you are going to do better speaking one on one to a manager in a professional manner. If you are planning on going on a trip that is going to take you over the 14 day return period and worried it might need returning just explain your concerns to the store manager and ask if an extended return policy is an issue.
Chapters seems to have better customer service and better managers in my experience. A store manager will normally quite happily make an exception in advance. Just get them to write the new return date on your reciept.