nor do banks give them out, at least not routinly. cheques would be the idea backup though for these types of situations, or say a local power outage.
no system is 100% reliable, have a backup.
can you say the nature of the cause? the seeminly random impact looks like reduced network capacity.
the missus has fallen out with Lidl over it, not because of the problem but the attitude, not telling any one there was problem then getting shirty with customers who only have cards.