Canceled without Cause

I changed my debit order to my new account with Discovery Bank, this was updated way before the 25th of the month. My Debit order is on the 1st. They confirmed the change and I allocated funds in the new account for the Debit order. The 1st went past, but no debit order went off. I checked their site, all seemed fine, I then mailed them (Reference ***) to try and sort this out, no response, I then wake up this morning with my discovery insured canceled. There has been no communication from their side, not response from their side, and then they ****ing go and cancel my insurance? ***. How can you treat a loyal customer like this? This is unacceptable on many levels