Oh, oh Vulcan wrote
"but they said you cant buy and sell in same account or ip address" "they could see what happened"
Vulcan, I can login in to trading account from my home computer, my work computer, my laptop, my iPhone app, the public library - even YOUR computer if you let me - each has its own IP address.
I think maybe those weren't really 'authorities' that called you - you didn't give any personal information over the phone did you? Like your name, trading account, bank info and IP address?
Did they start the conversation with "this is IBM and we've noticed some unusual activity on your account...."