Have you actually checked the email headers to see if it was in fact sent by Paxful? It could be a phishing attempt... ie. Scammer spoofs email from Paxful saying you've had a successful login and to "click here" if this was NOT you... "click here" link takes you to phishing site to try and get you to enter your Paxful login details.

If you have changed your password and/or locked the account... and you're still getting "Successful Login" emails, then chances are high they are just phishing emails.

To view the original message headers, open the message, click the '...' options button in the top-right corner of the message and then select "Show Original".