Why do you increase when service is terrible.

Very disappointed. I got an email the other day informing me that you will be increasing my monthly payments. While the increase amount is not huge, I still don't understand why it's increasing and not decreasing. My router has been paid off a very long time ago they connection keeps dropping for a good 10-15min at a time and I work from home, so that is very frustrating and over and above all of that I have asked on numourous occasions to pls change my debit order date to the 25th of a month, yet I still get debited at the end of a month. Just really, you're increase makes no sense with the service I have received this far.