Based on my past experience I would definitely try yet another email address if you're not receiving MyPoints emails.
Best way to rack up a lot of MyPoints for me seems to be Office Depot. I'm pretty bad about remembering to check portals like this before ordering online, but after getting 4000 points at once a couple times and 1000-2000 fairly easily just about every month (you can get that one only once a month) I do remember it for that.
I do click on all the 5-point emails, though. They add up too. For a long time that was the only way I earned points.
I just looked up my account, and amazingly it says I've been a member since 11/5/97!
8 years ago tomorrow. I had no idea it had even been around that long. No concept of long time periods anymore. Could be 4 years or 8, feels about the same....