hi im wondering about buying one of these phones tommorrow (most likely the k750i) the ebay listing says it wont work on cingular 850mhz and will work on 900/1800/1900mhz . i dont know what that means and i called the cingular rep and he said its not in their network. will the phone not work? i have cingular and i have no way of knowing.. please help! btw the phone says its unlocked