Contact the Margin Dept & claim you made a mistake. They will say that's there's nothing they can do about it & restrict you for 90 days. Tell them, you will have no choice, but to take your money elsewhere & close that account. They should let it slide if you have a good amount of cash in there.
Looks like all the answers you've received are wrong. They just restricted your account to cash only transactions for 90 days. It's not their rule but the SEC's rule. If you sell a stock you can use that money in 3 business days as that's what it takes to settle the funds. If you sell options it only takes one business day. So basically you can sell options today and use the money tomorrow to buy something else.