As the old saying goes: "Buyer beware!" It is much safer to buy a brand new console that even comes with a manufacturer's warrenty against defects than take your chances with used. I know PS3s can be expensive, but surely with a job you can save up enough cash for a brand new system in time if you can't get one right away. The extra cost for new is worth it in my mind. I never buy used consoles unless I am buying old consoles from past generations to relive childhood memories.
As for you, bcamp450. Don't ever buy used again, unless it's from a legit retailer. I know that this stinks, but treat it like a lesson learned. This is coming from a guy who has purchased two used PS3s, one 40GB from gamestop which I sold to get a 60GB refurbished from some company online from ebay, who now owns a brand new 320GB PS3 slim he purchased from best buy because the 60GB died (YLOD...how sad). Just buy the console new. You avoid so many headaches like this and you are getting brand new untouched hardware.
MAC address doesnt change its apart of the system or something, but only Jail Broken ps3's can change the MAC address though. But the only way I ever heard of getting MAC banned is by Merge Freezing
When you get a permanent ban Sony bans your PS3 console id which is unique to each console. They don't ban MAC addresses.
Umm yes they do, cause they cant ban the console id cause the console ID has nothing to do with PSN only the MAC does