In December, I was looking at my Discover Card statement (credit card, fairly common in the US), and realized that somehow, my 13% interest rate had snuck up to over 17% over the span of about 3 months.
So, I called, and asked them to move it back down. They said they would have to mail a form for me to fill out and return. I thought this was a bit stupid, as it seems like the only reason they couldn't do it over the phone is that they were hoping I would forget. I filled out their little form, and they responded in late January that they would move my interest rate back down to about 14%. Not perfect, but I could tolerate it. This was what showed up on my March bill.
So today, I opened my April statement, to see that the rate has snuck back up by a half of a percent. This is STUPID. I have very good credit and I pay my bills as soon as I get them, so there is no logical reason for the continuous increases except that they are greedy bastards.
I have sent a pissy e-mail to their customer service, asked that they fix it, apologize nicely and promise it won't happen again. If they don't, I will be closing the account next month, and using my other (8%) credit card exclusively.