Hertz Hertz Rental Hertz League City Hertz Rental League City Overcharged me and refuses to refund money. League City Texas

Got a rental because of an insurance claim. Waived the additional insurance, but it was added anyway costing me $150. I verbally told the girl I didn't want it and the signed on a credit card pad. There was no paper to verify she entered the information incorrectly. After multiple attempts of trying to find out what my charges would be, including that day, the day it was returned and a few days after, Rochelle kept telling me she didn't know and it would all be taken care of. They kept stating I "signed for it."  I escalated the situation and she lied to the corporate office to cover herself. Got a call from some guy in the office that was supposed to "investigate" and get back to me and, no surprise, no return call.