Xfinity bills keep going up.

When I signed up for Xfinity in May of last year I was told my bill would stay the same for 5 years. It has slowly crept higher and higher come to find out somehow it changed from a 5 year promotion to a 1 year promotion. I looked back at my first bill I ever got and it clearly states it was supposed to be a 5 year promotion. I’m upset and unless you guys can honor what was originally promised I will be switching internet providers.