Bill increased by 50%

I’ve send an email to head office, questioning my billing, taking the last 6 months I’ve received a 50% increase on my monthly installments, my concern is that they bill you excessively and when you questioned it they don’t bother replying back , they can’t blame it on call out fees because I only have 2 visit “slips” in my mailbox and who gives a 50% increase on any account these days , it just shows you the lack of customer service they have , I think it’s time to move to another service provider , luckily there is plenty competition in my area