Signed up for new service today, but my first bill is more that agreed on

I was paying $60.00 on my internet account, butI just signed up for a new internet plan (5 year guarantee price) this morning. My monthly bill was suppose to be $76.74 / Mo. I just received an email notice that my next bill will be $85.50. What is going on.  Why would there by around $10.00 higher.