Hertz customer service/response dismal

Rented a car through Hertz at Lanseria for two days on the 8th of October till 10th of October, returned car in same good order with full tank etc, blocked my whole credit card (which a was fine with for the duration of rental) - contact them on the 16th regarding the credit card amount release, received no response to date and card is still blocked..?

I contact them through email and chat service, chat service said a representative will phone me but to date hasn't done so hence the complaint.