Do knockback effects stack?

[valkry]

Maybe not all of them, but at least know all the ones with the last year or so accoring to some...

[Bigfish]

Credit card not working - Enabled to protect me from credit card theft

Yeah, I've had that happen a couple of times. Apparently it raises a flag if you buy ten (or four) of something in quick succession like that. A phone call to the CC company can usually clear it up.

[Catamer]

make sure your bank didn't block your card.
contact your bank, call the number on the back of the card.

I had mine turned off or a block on it until I called them and told them I would be charging multiple times...
I found it easier to upgrade by buying the upgrade box at the store than to do it online because my bank HATED it when 5 or 10 charges come through from the same place like Bliz

[Leon]

If my Experiences in VH on my Warrior attest to yes they do - being thrown across the main floor by Knock backs from the dragonkin on a few occasions