I had the account for a long time had hundreds of mils no problems, lost a big amount at the duel arena so i needed to buy some. woke up today my inv had slayer 1gp items like enchanted gem earmuffs...etc no gp had like 8m, but fury ammy other items not taken, just what I was wearing from the gp I bought.
Your account must have been compromised by someone, I suggest changing your e-mail information as well as your account information. Don't forget the 2FA (Authenticate) your email and OSRS account.