Credit card 'layaway'

This evening my Santander credit card failed to work in the machine three times in M&S and then the cashier started ringing the bell for a supervisor. When the supervisor arrived the cashier announced that it was a 'layaway.' The till even produced a ticket with Layaway printed on it. The cashier and supervisor then gave each other some looks and I was removed to the customer services desk. The transaction was repeated and my card worked just fine. I've tried to google what this was all about but layaways only seem to mean a repayment method. Can any of you who work at M&S or any other retailers shed light on what this was all about please? I was so naffed off thatI didn't want to spend any more time in there so I didn't ask. The cashier had asked three different supervisors in the space of five minutes if she could have a toilet break which also got on my pip as I didn't need to know that. The transaction was for about £35.00.