Absolutely nightmarish ordering process

I have just placed the same order for a seventh time after all previous orders were automatically cancelled.  The second time they cancelled it, I received an e-mail saying Dell needed me to call to confirm or the order would be automatically cancelled.  I called, and was told to reply to the e-mail with the words "I confirm the order."  I did this, following the representative's instructions.  The order was still cancelled - AFTER two pieces of it were already shipped.  One of those pieces will be at my house tomorrow.

I was told that there was an issue with my billing address.  That's not super hard to believe as I recently moved and changed addresses, so it's possible wires were crossed.   But no, my bank has (and has had for a while now) my current shipping address as my billing address.  Still, in the previous six orders I've tried to make I've tried both billing addresses on the off-chance something wasn't right.

I called my bank, who told me "we keep authorizing the funds, Dell keeps refunding it.  It's not declined, it's not an unauthorized transfer.  You should contact Dell and try to find out what's going on."

Every time I spoke with someone on the phone (from various phone numbers I was given to "validate" or "verify" my account, I was told to do something I had already done (or an agent had done on my behalf).  For example, I was told to include my "customer number" the next time I tried my order.  The very helpful chat agent who placed my order DID include my customer number.  Then I was advised to use the correct billing address.  Again, I did this multiple times.

Finally, a phone agent told me that my card had been tried too many times and that it had been flagged.  I informed this person that I had followed their instructions the first time I was contacted about this order and it was automatically cancelled anyway.  I asked "So because of your mistake, I can't make this purchase?", and they replied "yes."

This is beyond absurd.  I want to give Dell money for a computer.  My bank wants to give Dell my money for a computer.  Dell, it appears, does not want my money.  So enough is enough.  If (and when) this latest order is cancelled, I will give it to another company.