Can a customer pay half in cash and the rest on a card?

Yes, and not as an exception. A bill does not have to be settled by one method: it can be spread across several, so two people paying for one table between them is an ordinary transaction rather than something the counter has to work around. Cash and card are the everyday case, and the till treats a part payment the same way it treats a whole one — what is left to pay is simply what is left.

Where the money is taken from changes who processes it, and that is a setup decision rather than something a cashier thinks about. A sale rung up online, one taken at a self-service kiosk, and one taken on a terminal that has lost its connection each go through a different processor — AxiataPay, Finexus and PMA respectively. Which of those a shop needs follows from how it sells; the integrations page sets out what each one covers.

The point of all of it is that the counter stays simple. A customer decides how they want to pay, staff take it, and nothing about the arrangement behind it has to reach the person standing at the till.