PayPal Button Stopped Working

This form used to have a PayPal payment button at the bottom of it until a couple of days ago, but now we just see this code instead.

[paypalsubmit id:wpcf7-pp-submit-1 class:btn class:btn-success class:wpcf7-pp-submit email:[email protected] currency:GBP itemamount:payment-total itemname:payment-course quantity:payment-quantity return_url:https://https://skillzschool.co.uk/payment-successful cancel_url:https://https://skillzschool.co.uk/payment-cancelled “Submit Details & Proceed to Payment”]

Has anybody come across this before please or can point us in the right direction to fix it? Thank you in advance.

The page I need help with: [log in to see the link]