Sadly, we live in a world dominated by fear.

Seems like the obvious response would read:

Dear Louise Vermillion,

Thank you for your letter dated December 14, informing me of your bank's policies with respect to cryptocurrency transactions.

I see from your salutation that you are the bank's "Loss Prevention Officer," and I regret to inform you that you have failed at your job, as I hereby must inform you that you have lost my business, effective immediately.

The cryptocurrency industry is growing rapidly, and currently represents a wealth base approximately 1000 times the size of your organization's capitalization. However, as long as the USA remains a free country, I fully support your right to stand in the way of progress.

Yours sincerely,
Jordan B. Spencer