Should actually read your EOB's. You can find out if the provider is billing for services that you did not get. Also, the practice that I am in, we bill at the completion of services. Sometimes that is 4-8 or 10 weeks after we start providing services. But, with each weekly fill there is often a co-pay on that fill, so, when you get a bill after 10 weeks for your cumulative co-pay, and complain, we can say, please read your EOB and it will show that it was filled 10 times, your co-pay for each fill is 5 bucks, ergo the 50 dollar charge.
It is a summary of what the insurance company is paying, what the office billed, what your share is. READ IT AT LEAST