Hello , I am arriving at Hong Kong and I need to be at least 72 hrs in Zhuhai.

You can get Zhuhai VOA on arrival in Zhuhai and not in Hong Kong. You will take a bus from Hong Kong to Zhuhai over the HZMB bridge and will obtain your Zhuhai VOA on arrival at Zhuhai port that is located on the artificial island just before Zhuhai. The alternative is to take a ferry from Hong Kong to Jiuzhou port in Zhuhai. Please, just have in mind to book your accommodation in advance, at least for just one overnight and have a confirmation in hard copy, ready to present it to immigration official. Also, it is advisable to have the amount that should be paid for Zhuhai VOA (it is 168 CNY for French citizens, as far as I know) in CNY in cash. You can buy CNY at any money changer office in Hong Kong.

Visa /Mastercard is also accepted at the HK-Zhuhai-Macao Bridge port in Zhuhai for the 3 day VOA (I can't confirm the same for Jiuzhou Port, Gongbei or Hengqin).

A friend visited Zhuhai last week and offered 200RMB cash. The staff offered Visa/Mastercard as an alternative (maybe they didnt have enough change). He used an Australian Visa Card.

Still better to prepare cash!

I can confirm that both the Zhuhai side of HK Bridge Port and Gongbei offer Visa/Mastercard as payment options. On this basis I assume Hengqin Port also does but I can't confirm it.