Pablo_Oujdii - Jagex will never private message a player within the game to invite them to one of the mod teams, but rather will only communicate such information via the message centre accessed via the Account button at the top of the website. In addition, Jagex mods, should they private message you or chat ingame, will always have a gold crown in front of their name.
This player wasn't a Jagex mod, but rather was a scammer attempting to phish account information from you. They were able to do this by directing you to the fake website that you filled your account information into.
At this point, the best thing to do would be to take steps to
Secure your computer and account
to ensure the hijacker no longer has access. Jagex is unable to return items lost in a hijacking, and this is explained further in their
Lost Items
support article.
Should you need any further assistance with securing your account, feel free to create a thread within the
Account Help forum
and the community helper team will be more than happy to assist.