Thanks @markowl, we did get that email today. However I phoned them on Tuesday and luckily enough got through after about 15 mins of pressing redial.
The money was actually refunded the same date, which we didn’t notice until checking today. That includes the initial deposits which were on out of date cards (which they suggested would take longer to refund).
So all sorted now. Probably won’t travel with them again, despite the apology email.