Board Thread:ROBLOX help and discussion/@comment-34225103-20180105152209/@comment-4196050-20180105152848

Hi! I understand that this situation is very frustrating for you. Roblox staff do not know if it was you or a "friend" who made something on your account. It was your account that made the model, it violated the ToS, so Roblox took appropriate moderation action.

This is one of the main reasons why you sharing accounts is not recommended. For many online games and websites, it says something in the ToS that you are responsible for whatever happens on your account, even if you are not the person who did it.