Barclaycard Rewards MasterCard deceptive practice regarding rewards credit, Internet

I originally opened a JoAnn's MC with Juniper Bank which was changed to Barclay's.

The JoAnn MC was replaced by a Barclaycard Rewards MasterCard.

I had this account for 4 years and always paid on time and in full every month. I have an excellant credit rating but this company doesn't care.

Their rewards program only allows you to use the points if it will cover an entire transaction.  My September balance (due Oct 11) was from one transaction of $29.44.  I decided to use my rewads points to cover this transaction.  The credit of $29.44 posted to my account Sept 23rd, which should have made my balance on my account $0, so I did not send a payment since that was my entire balance.  When I looked at my statement this month there was a $20 fee for not making a payment by Oct 11.  When I called customer service I was told the credit was not considered a payment and I still needed to make a payment.  They would not remove the fee from my account unless I made a payment over the phone right then and I told them I would not give my bank information over the phone to them and would schedule my payment myself and was told in that case they could not remove the $20 fee.

I don't understand why I should have to make a payment when my balance was 0 after the credit and if they require you to have enough reward points to cover an entire transaction why that doesn't cover it on your bill.

I have closed this account and do not intend to do business with this bank again.  There are other much more consumer friendly banks available that will not try to pile fees on however they can.