Error pay php 7.2

-- url of the page with the problem -- : www.hermanosgaliano.es
-- HikaShop version -- : 3.5.1
-- Joomla version -- : 3.8.12
-- PHP version -- : 7.2
-- Browser(s) name and version -- : 7.2
-- Error-message(debug-mod must be tuned on) -- : Call to undefined function mcrypt_encrypt()


Hi.
With the PHP 7.2 version of Joomla this error appears when the customer places an order to pay by card.

Call to undefined function mcrypt_encrypt()




What can we do?

Hi.
I sent an internal message ( www.hikashop.com/support/contact-us.html ) informing that right now the php is in 7.0, so the test can not be done ...