You should make sure to not give your details to anyone, no matter what the purpose is. As soon as they ask, you should block them and report them immediately to us. 

Keep in mind that account sharing is also against Roblox Terms of Use, as quoted below and can result in action taken on your account. 

"You are responsible for maintaining the confidentiality and security of any credentials used to access your Account (e.g., a username and password). You must not share or disclose such credentials to others (except for Guardians in the case of a Minor User)." - Roblox Terms of Use, Section 2: User Accounts; Access to Services., Paragraph B: Securing an Account.