Paypal Payment Pro - Adding a Captcha / ReCaptcha to Confirm

We use Paypal Payments Pro with OpenCart 1.5.6 and PayPal is saying a fraudsters are running a script to test stolen credit cards. We are getting like over 10,000+ declines. They want us to add a captcha to checkout process to stop them.

Is it possible to add a ReCaptcha or Captcha to the bottom of checkout form, for the final step before someone can click on "Confirm Order"?

PayPal says the these methods below should be impleted, but I don't see any options in OpenCart for them:

·Velocity Checks

Velocity refers to the number or speed of payments made within a certain period of time – ten payments sent from the same customer within seconds or minutes of each other, for instance. Monitoring this activity is important. Even with donation sites, it may be unusual for a user to make low dollar payments in rapid-fire succession. Payment velocity can be monitored by dollar amount, user IP, billing address, BIN, or device.

.Shopping Cart Session Velocity

This refers to the number of times that one buyer can attempt to complete an order in one shopping cart session. By putting a limit on the attempts in one checkout session, it will allow for the visibility of shopping cart declines, which may assist in identifying a possible carding situation.

We are running Opencart Version 2.3.0.2, and are having the same issue.

What did you do?