Billing Issue

I am having a billing issue and am VERY FRUSTRATED trying to resolve it via chat with a live representative. I had a cable box that was not working. I took it back to the store and received a new one. After MANY issues (no fault of my own!!! The fault of the store employee!), I finally had the new cable box working. However I was charged and service fee of $100.00 and a couple of service fees. The chat agent looked into it and assured me that my August bill would be $217.00 (taking off those fees) and my next bill and all bills going forward would be $316.00. I just checked, and my August bill is $343.24. So, after spending hours on chat for 3 days, absolutely nothing was resolved. Please take care of this.