Computer generated taxes and fees monthly

After speaking with an agent today, she confirmed that my mobile (unlimited data plan) arbitrarily increases each month due to taxes and "computer generated fees."

I find it hard to believe this is legal and not actionable to arbitrarily increase customers' bills each month when the plans, usage and insurance are static. 

I'm aware of the data breach class action. But, I'm sure a class action like the one against Sprint and the banks charging overdraft fees is in order here. Customers cannot set a budget if Xfinity is nickle and diming us to death increasing our bill by a few dollars each month like we won't notice. 

This is shameful and criminal.