Using achievement unlockers, profile editors, or save mods on Xbox Live violates the Microsoft Services Agreement and Xbox Live Code of Conduct. Enforcement is strict and often permanent.
Microsoft rarely overturns achievement bans. Excuses like "I didn't know," "A friend did it," or "Offline only" are not accepted. The device/account is considered compromised.
Play fair. The risk (losing your entire digital library + hardware access) is infinite; the reward (fake Gamerscore) is zero.