Policy cancelled without any notice given

Debit order bounced after December. Today I contact Discovery Insure to settle only to be told my policy was cancelled. I received no communicaton or correspondence to this effect (due to a system glitch I was told). Even though it was resolved on the phone and apologies rendered by custome service, after being a client for many years I think its time to move elsewhere (switch & save...?) since I was not aware I had no cover.