I'm having the same problems. It started a couple of days ago when I was unable to download songs from my shopping cart. When I pressed the 'Buy Now' button, I received a 502 error. iTunes did not download my music so I tried again...then again...and again. Still nothing! I was concerned but figured there was a temporary problem. Later, I checked my email and I was astonished to find several PayPal receipts for my purchases at the iTunes store!! What a mess! Apparently when I pressed the 'Buy Now' button I was actually purchasing the songs even though I was never able to download them! I contacted support and they kindly refunded everything (which totalled over $50) without an explanation as to what happened or what an error 502 was! Tonight I tried again (thinking it was just a fluke) and received the 'credit card orders cannot be processed now...' error. Not sure what's going on. I never had this problem before. I hope they correct this soon.