I haven't had any problems either with stamps.com... so.. yeah.
Anyway, you aren't going to find another site exactly like yourfree360games.com, because Trainn doesn't have the equivalent for the other consoles. However, there are other freebie companies who do similar things, such as videogames.git-r-free.com or customorderthis.com, which will let you custom order gifts.
Another problem for you will be that Stamps.com on many sites has been downgraded and usually won't give full credit. They'll usually give you something like .25 credits or such. Even on Trainn's other site, Stamps.com is no longer a full credit offer.
Aside from Trainn sites, I don't see Blockbuster on many freebie site's offer list. This is most likely because the Blockbuster offer usually doesn't credit very well, and many sites have to MCR it and they don't get paid for it. However, you will find the Netflix offer on many sites, since it does credit well, but it just takes a lot longer to get credit for it.
So, whatever freebie site you choose, you should look into signing up referred. You should be able find someone who would be willing to pay you for signing up under them.