PHP Credit Card Processing Script to run under PHP 7.3

We currently run a manual online auction checkout through our website coded in PHP. It is a one page form where the customer inputs their order number, billing info, and credit card details before submitting a one time payment. Our current processing gateway is through Authorize.net. The script we are using is about 10 years old, and no longer functions when upgrading from PHP5 to PHP7.

https://redstradingpost.com/checkout/payment.php

What we need is to have the existing script replaced with a new or updated system to meet our needs and function properly. We would also like to be as proactive as possible in ensuring that it will remain functional and secure for as long as possible. The current source is a one page script that both creates the form and processes the payment. We have staff on hand that can handle any styling changes, and just need the form to be functional under PHP7.

Full FTP and Control Panel access will be available to the developer we choose to complete this project.

Please feel free to ask questions and we will be more than happy to answer.