Rogue company !!!

Rogue company !!!
I made a purchase online of 12 installments with 0% interest. I got the first and second invoice. But the third never showed up, I was in contact with Svea Customer Service and questioned them why I have not received my invoice for November? So that was the answer to my question:
"Hello,

Thanks for your mail.
Unfortunately, avin for November has expired and the terms have thus been changed to general terms, which means that an annual interest rate of 19.50% is imposed from here on. "

Completely senseless to change the terms to 19.50% annual interest rate without a single reminder!
Rather, I see this as a trap for collecting interest money!

A few days later I received confirmation that my invoice had not arrived.

The invoice for November which was sent 2017-11-13 would therefore be paid as usual. If you missed the invoice for November, you would have had to contact us to notify us. We do not know if the invoice, for example, disappears in the postal service. This time, the invoice for November had come back to us in return because the mail could not deliver correctly when C / o was missing. "

I called their customer service, explaining that Me and my wife live at the address why a C / O is needed? While I have always received my letters through the address that you feel is missing C / O

He commented on my question like this:

If the item returns an invoice to us then we discard the invoice and instead send a reminder we adjust the terms to 19.50% annual interest rate.

In my eyes Svea Eknomi / Finans are bandits and they have planned well to indebted people and create imbalance in society.