I see that the question was previously addressed with an outline of how to file a complaint with FINRA. While that could be an appropriate next step, engaging an attorney will certainly be appropriate when you see fit to do so.
You should have a written request for response, sent certified mail, return receipt requested, in your files. This letter should outline the name of account, date of trade, copies of account transcripts that do not reflect the transaction, copies of your remittance proof, and a chronology of phone calls you made to inquire, with dates and contact personnel. I also like to ask for the name of their malpractice carrier.
Send a copy to the in charge broker and one to the office manager. Send it to FINRA if you like. Give them a reasonable deadline response date, and the contact information for your attorney if you engage one now.
You will then be handing off a complete file for your attorney to represent your interests.
I have seen these handled by general practice attorneys, so a call to your local Bar Association will likely generate a number of qualified attorneys and firms to assist.
I am troubled by " I purchased some stock a long time ago and have confirmation number from Ameritrade". There may be issues with the timeliness of your request, which your attorney can address.
I hope that adds to the previously issued opinion from the other expert.
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