Sorry for the thread necro, I wish I had read this earlier, I now too have had my Steam Account stolen and is in the hands of Steam support.
I stupidly clicked a link on discord for a free $50 steam gift card, took me to a steam community page, that looked legit, with a number going up of what I thought were gift cards being claimed.
I then signed into the steam community page hoping to claim my free $50 gift card, I even was sent a security code to my email to input, I then put in the code, didn't get a free gift card.
A few minutes later, I noticed I was signed out of my steam client, tried putting in my details and they were no longer registered
Spent hours researching and trying to get into my account then finally I managed to somehow self-lock my steam account and get in contact with steam support.
Told them everything and here we are, no account and all my games no longer available to me.
Luckily I didn't link a Paypal account and just sign in manually to Paypal on each transaction.
Had one reply from Steam, asking for more information, that came about 8 hours after I logged my ticket.
I'm praying I can get it sorted