Fidelity Blocked My Account Without Explanation – Has This Happened to Anyone Else?

I woke up recently to a message from Fidelity stating, "Your account has been blocked," when I tried to log in. I’ve had both a brokerage account and multiple CMA accounts with them for about a year and a half.

After calling the number provided, I was informed that I am no longer allowed to use Fidelity’s services. When I asked for a reason, they refused to disclose it. However, they did request a medallion signature and a letter of instruction for a check I deposited in August 2024 for around $300. This was the only check I’ve ever cashed with Fidelity, and it came from my girlfriend’s family as reimbursement for covering her moving expenses.

I’m very close with her family and know with 100% certainty that they wouldn’t have reported any issues with the check. Despite this, Fidelity closed my account, locked me out of my investments and funds, and won’t release anything until I comply with their process—which includes getting my girlfriend’s extended family involved. They also requested my business statements from Stripe, which I have no issue providing (I had set up Stripe to auto-deposit to my CMA).

Has anyone else experienced something similar? What steps did you take to resolve it?