They're not going to sue you.
They may contact Paypal though and the money you received may be removed, plus your account may be flagged/limited/closed.
Even after 45 days, they can still get the money back. I'd recommend you do not spend it. If you do spend it, and it's taken, the account will have a negative balance which you must pay back, which means you'll be in debt.
You have two options: give the account back, or sit, wait, and risk losing the money.
Link to my guide: https://www.mmowned.com/forums/wow-g...rd-policy.html | I'm retired, please don't PM me. Thanks.