AITA -SumUp requires cc info in plaintext

I was trying to make a purchase from a local vendor that uses SumUp for credit card processing. The vendor told me SumUp wanted verification via a 'Receipt of Goods and Services' pdf form, that I would fill out, and email or text back to the vendor, and the vendor would email or text it back to SumUp. The form required that I enter my complete credit card information, including expiration and CVV - to be sent in plaintext via email and/or sms text. The vendor is a non-tech savvy friend, so I called SumUp to inquire, and they thought it was all fine. I found another way to pay my friend. AITA?