Yesterday I found out I have been paying them too much for one year. All of a sudden, one year ago, they increased the price (probably just for me) and billed me twice each month. I didn't even notice and of course, you can blame me for being so stupid. Was it a system error or something else they should have notified me because they would have obviously noticed it... I don't know what it was. I have let them know and been waiting for their decision.