Credit card scam

Here is what happened. I have a credit card account with Advanta Bank Corp. My bills were being delivered regularly for about 6 months. Then my bills stopped. Here is what I found out. Someone at Advanta sent my bill to a non-existing address. Advanta has this information on file. By the time I found out what was going on, my payment was past due. This was the only payment Advanta received late. It was due to their incompetence. Advanta is using this reason to raise my interest rate from zero to over 25%. Numerous calls to Advanta did nothing. It seems that they are concerned only with their new found income stream. How many other account holders have had this happen to them also? I have decided to fight what I believe is unethical, maybe even illegal. If you are interested, I can send you information that I have. Thank you.