Selling gold on World of Warcraft is risky business. There is no way around that fact.
From Blizzard's wow gold press release:
"In keeping with Blizzard's aggressive stance against cheating in World of Warcraft, we banned over 30,000 accounts in the month of May (2006), and with that removed well over 30 million gold from the economy across all realms. The banned accounts were taking part in activities that violate the game's Terms of Use, including using third-party wow gold programs to farm gold and items, which severely impacts the economy of a realm and the overall game enjoyment for all players."