Refund of deposit not received from Europcar

I had rented Europcar vehicles in New Zealand from 6th to 9th Feb, 2018 and 9th to 18th Feb, 2018. Details of the booking are given below:

1) Ford Mustang Booking Referece No: ********** 529 Pick Up Date: 6th Feb, 2018 Pick Up location: Auckland Airport Drop Date: 9th Feb, 2018 Drop Location: Auckland Airport

2) Holden Astra Booking Reference No: ********** 267 Pick Up Date: 9th Feb, 2018 Pick Up location: Queenstown Airport Drop Date: 18th Feb, 2018 Drop Location: Christchurch Airport

I have the following complaints regarding my rental: 1) I have not received the refund of 400NZD (200NZD for each booking) in my account yet. I have mailed Europcar but have not received any response. My credit card bill due date is in a week. It's absolutely shameful that Europcar isn't responding to mre

2) I was charged 41.4NZD as navigation charges for Ford Mustang (Booking Reference No: ********** 529) but there was no separate device given and navigation was a part of the vehicle. I want this amount refunded as well. No response from Europcar on this either. Can someone please get in touch with me? Am now at my wits end.