Enterprise Rent-A-Car Review

My husband's company rented this car for us, three months ago. When we went there to pick up the car, we just sign the contract as we taught that it's all about the agreement between them and the cowpony. they also took our credit card and said they just need it as a deposit. but after three months we understand that they charged our credit card 750 $ per months for the insurance that we didn't need at all. and it costs us 2250 $ for 3 months. we went there and they said you signed the contract and we couldn't do any thing. 

now we should pay 2250$ for nothing, what do you think about such a company???????????