incorrect eToll charge
 

I am sure this happens a lot in the states. Since I accidently paid a toll with not having the box closed a couple of years ago, I always make sure, that I keep it closed. Now they have just charged me a week of service plus a 50 cent toll in Texas. Problem. I rented AND dropped off the car 1500 miles away from that toll booth, and only drove 1100 miles in total.
Will costumer service take care of it (as it is very obvious), or do I need to dispute the charge on my credit card?

Call them.

I usually do a dispute as a last resort. Once you've exhausted all you options and have made the necessary inquiries will a dispute be more likely to succeed.